Adsorptive amputation of hazardous azo dye Congo red from wastewater: a critical review
Nirav P. Raval1 • Prapti U. Shah1 • Nisha K. Shah2
Abstract Increasing amount of dyes in an ecosystem has propelled the search of various methods for dye removal. Amongst all the methods, adsorption occupies a prominent place in dye removal. Keeping this in mind, many adsorbents used for the removal of hazardous anionic azo dye Congo red (CR) from aqueous medium were reviewed by the authors. The main objectives behind this review article are to assemble the information on scattered adsorbents and enlighten the wide range of potentially effective adsorbents for CR removal. Thus, CR sorption by various adsorbents such as activated carbon, non-conventional low-cost materials, nanomaterials, composites and nanocomposites are surveyed and critically reviewed as well as their sorption capacities are also com- pared. This review also explores the grey areas of the adsorp- tion performance of various adsorbents with reference to the effects of pH, contact time, initial dye concentration and ad- sorbent dosage. The equilibrium adsorption isotherm, kinetic and thermodynamic data of different adsorbents used for CR removal were also analysed. It is evident from a literature survey of more than 290 published papers that nanoparticle and nanocomposite adsorbents have demonstrated outstand- ing adsorption capabilities for CR.
Keywords Adsorption . Congo red . Adsorbent . Nanoparticle . Nanocomposite
Responsible editor: Philippe Garrigues
Abbreviations
AC Activated carbon MWNC Multi-walled nanocarbon
CAC Commercial activated carbon
PAC Powdered activated carbon
KJA Sub-bituminous coal from Kazimierz-Juliusz mine (KJA series)
SA High volatile bituminous coal from Szczyg1owice mine (SA)
KJA/Ti KJ coal impregnated with titanium
oxide acetylacetonate
SA/N/CaFe SA coal treated with nitric acid (N) and Ca- and Fe-exchanged coals
KJA/N/CaFe KJ coal treated with nitric acid (N) and Ca- and Fe-exchanged coals
KJA/S/CaFe KJ coal treated with sulfuric acid (S)
and Ca- and Fe-exchanged coals DRZAC Activated carbon prepared from Delonix
regia pods (flame tree) activated with zinc chloride
GAC Granular activated carbon
ACL Activated carbon—laboratory grade
ACC Activated carbon—commercial grade
ACF Microporous activated carbon fiber
SC Straw carbon
RHC Rice husk carbon
CSC Coconut shell carbon
GPC Grapefruit peel carbon
* Nisha K. Shah [email protected]
1 Department of Environmental Science, School of Sciences, Gujarat University, Ahmedabad, Gujarat 380009, India
2 Department of Chemistry, School of Sciences, Gujarat University, Ahmedabad, Gujarat 380009, India
BDC Bamboo dust carbon
GNSC Groundnut shell carbon
GPAC Guava peel-based activated carbon GPUC Guava peel-based unactivated carbon OSAC Activated carbon produced from
olive stones
GNC Groundnut shell charcoal
EC Eichhornia charcoal
BSC Bael shell carbon
NSDC Neem sawdust carbon WNMC Water nut-modified carbon
AC-MC Activated carbon prepared from
Myrtus communis
AC-PG Activated carbon prepared from
pomegranate
RHCAS Rice husk carbon activated by steam ASPRHC Steam-activated pigmented rice
husk carbon
Amongst all the other dyes, azo dyes pertain to the largest class of synthetic dyes because it accounts for 60–70 % of the dyes’ total consumption. Azo dyes are complex aromatic com- pounds with significant structural miscellany and are of seri- ous environmental concern because the reductive cleavage of azo linkages is accountable for the formation of amines, which are classified as toxic and carcinogenic.
Congo red (CR) [1-naphthalene sulfonic acid, 3,3′-(4,4′- biphenylenebis(azo))bis(4-amino-)disodium salt] is a benzidine-based anionic diazo dye prepared by coupling tetrazotized benzidine with two molecules of naphthionic acid
AuNPs-coated AC
AgNPs-coated AC
D-R
isotherm
Gold nanoparticles (AuNPs)-coated activated carbon (AC)
Silver nanoparticles (AuNPs)-coated activated carbon (AC) [coinage NPs] Dubinin-Radushkevich isotherm
(Table 1 shows the physico-chemical properties of CR). It is anticipated to metabolize to benzidine, which is a known hu- man carcinogen (Zeng et al. 2014). It has a complex chemical structure, high solubility in an aqueous solution and highly persistent nature once it is being discharged in the environment (Chatterjee et al. 2010b). Although CR, a human carcinogen,
R-P model Redlich-Peterson model LCAs Low-cost adsorbents
EMHS Electrocoagulated metal hydroxide
sludge
MHS Metal hydroxide sludge
BFA Bagasse fly ash
Introduction
Synthetic dyes are extensively used in many industries such as textile, leather, paper, printing, food, cosmetics, paint, pig- ments, petroleum, solvent, rubber, plastic, pesticide, wood preserving chemicals and pharmaceutical industry and have received increased consideration for several decades because discharge of these dyes contaminated effluent is related with water pollution (Mohammadi et al. 2014).
At present, more than 100,000 commercial dyes are known with an annual production of over 7 × 105 tonnes/year. Textile industries consume two thirds of the dye manufactured, i.e. more than 10,000 tonnes/year, and out of this consumption, approximately 100 tonnes of dyes per year is discharged into waste streams. In addition to this, all other industries allied with dyes also generate voluminous coloured wastewater (Yagub et al. 2012).
The colour is one of the first contaminant to be recognized in wastewater and the presence of even very small amounts of dyes in water is highly discernible and inadmissible because it averts reoxygenation in water. Beyond this, it also inhibits the penetration of sunlight and thereby disrupts the biological activity of aquatic organisms. In addition, because of the toxic, carcinogenic, mutagenic and allergic nature of dyes, the dis- charge of dyes containing effluents in natural waters can pose hazardous effects on the living systems (Zaini et al. 2014; Sarkar et al. 2014).
has been banned in many countries due to health hazards, but it is still widely consumed in several countries(Afkhami and Moosavi 2010) and many treatment processes have been used for the removal of CR from water and wastewater such as photocatalytic degradation (Lachheb et al. 2002; Erdemoğlu et al. 2008; Gomathi Devi et al. 2009; Devi et al. 2010; Sakkas et al. 2010; Uti et al. 2011; Murcia et al. 2011; Guo et al. 2013; Sui et al. 2013; Gupta et al. 2013b; Bagheri et al. 2014; Tekin 2014; Pawar et al. 2014; Chen et al. 2015), sonochemical degradation (Sistla and Chintalapati 2008; Gopinath et al. 2010), sonophotocatalytic degradation (Bejarano-Pérez and Suárez-Herrera 2007; Pang and Abdullah 2012), electrochemical processes (Öğütveren and Koparal 1992), ozonation (Gharbani et al. 2008; Khadhraoui et al. 2009; Faouzi Elahmadi et al. 2009), oxidation processes (Kondru et al. 2009; Wang et al. 2013a; Venkatesh et al. 2014), electro-Fenton process (Lahkimi et al. 2006), Fenton-biological treatment (Lodha and Chaudhari 2007), enzymatic decoloration (Ahmedi et al. 2015) and biological degradation (Chakraborty et al. 2013; Chander et al. 2014; Neoh et al. 2015). Amongst all these techniques, adsorption has become one of the most economical, effective and widely used treat- ment techniques for the removal of CR from aqueous media, and many research papers have also been published on the adsorption of CR.
Although there are a number of review articles such as
BMicrobial decolorization of textile-dye containing effluents: a review^ by Banat et al. (1996), BFungal decolorization of dye wastewaters: a review^ by Fu and Viraraghavan (2001),
BRemediation of dyes in textile effluent: a critical review on current treatment technologies with a proposed alternative^ by Robinson et al. (2001), BThe removal of colour from textile
wastewater using whole bacterial cells: a review^ by Pearce
et al. (2003), BRemoval of synthetic dyes from wastewaters: a review^ by Forgacs et al. (2004), BDecolourization of indus- trial effluents—available methods and emerging
Table 1 Physico- chemical properties of the dye Congo red
Parameters Value
Dye class Azo dye
CAS no. 573–58–0
Synonyms C.I. 22120, Congo red 4B, Cosmos Red, Cotton Red B, Cotton Red C, Direct Red 28, Direct Red R, Direct Red Y
IUPAC name 1-Naphthalene sulfonic acid, 3,3′-(4,4′-biphenylenebis (azo))bis(4-amino-)disodium salt Molecular weight (g/mol) 696.68
Molecular formula C32H22N6Na2O6S2
Melting point >360 °C
pH range 3.0–5.0
Solubility Soluble in water and ethanol; very slightly soluble in acetone; insoluble in ether and xylene Molecular structure
technologies—a review^ by Anjaneyulu et al. (2005), BAdsorption-desorption characteristics of phenol and reactive dyes from aqueous solution on mesoporous activated carbon
prepared from waste tires^ by Tanthapanichakoon et al. (2005), BNon-conventional low-cost adsorbents for dye re- moval: a review^ by Crini (2006), BMethods of dye removal
from dye house effluent—an overview^ by Mondal (2008),
BAgricultural based activated carbons for the removal of dyes from aqueous solutions: a review^ by Demirbas (2009),
BApplication of low-cost adsorbents for dye removal—a review^ by Gupta and Suhas (2009), BBiodegradation of syn- thetic dyes—a review^ by Ali (2010), BDecolorization of dye wastewaters by biosorbents: a review^ by Srinivasan and
Viraraghavan (2010), BCationic and anionic dye adsorption by agricultural solid wastes: a comprehensive review^ by
Salleh et al. (2011), BA review on applicability of naturally available adsorbents for the removal of hazardous dyes from aqueous waste^ by Sharma et al. (2011), BAdsorption of dyes
and heavy metal ions by chitosan composites: a review^ by
Wan Ngah et al. (2011), BMicrobial decolouration of azo dyes: a review^ by Solís et al. (2012), BAdsorption of dyes using different types of sand : a review^ by Bello et al. (2013),
BAdsorptive removal of dyes from aqueous solution onto car- bon nanotubes: a review^ by Gupta et al. (2013a), BReview on dye removal from its aqueous solution into alternative cost
effective and non-conventional adsorbents^ by Dawood and Sen (2014), BAgricultural peels for dye adsorption: a review of recent literature^ by Anastopoulos and Kyzas (2014),
BMagnetic composite an environmental super adsorbent for dye sequestration—a review^ by Sivashankar et al. (2014), BDye and its removal from aqueous solution by adsorption:
a review^ by Yagub et al. (2014) and BRecent advances in new
generation dye removal technologies: novel search for ap- proaches to reprocess wastewater^ by Ahmad et al. (2015), but they all provide scattered information on the dye removal, and beyond that, none has given complete enlightenment about all the adsorbents that had been used for one specific dye.
Therefore, the present review article deals with the critical review information on the various adsorbents for CR removal from water and wastewater. The main objectives of this review article are to compile an extensive list of adsorbents from the literature and provide a comprehensive up-to-date research summary on various adsorbents that have been reported. The authors strongly encourage the readers to refer to the original research articles for information regarding the experimental conditions.
Literature on various adsorbents used for the removal of CR
Activated carbon adsorbents
Activated carbon is a crude form of graphite having a random or amorphous highly porous structure with a variety of pore sizes ranging from visible cracks and crevices to crevices of molecular dimensions (Hamerlinck et al. 1994). It is the most widely used adsorbent for different classes of dyes, i.e. acid, direct, basic, disperse, reactive, etc. (Al-Degs et al. 2000) mainly because of its prolonged surface area, high adsorption capacity, microporous structure and special surface reactivity (Marsh and Reinoso 2006).
There are different physical forms in which activated car- bon (AC) is used such as powdered, granulated, fibrous, spherical and cloth forms. Powdered activated carbon (PAC) has a very fine particle size of about 44 μm, which permits faster adsorption. The granulated activated carbon (GAC) has granules of 0.6 to 4.0 mm in size and is hard, abrasion resistant and relatively dense to withstand operating conditions. The fibrous activated carbon fiber (ACF) has a large surface area and contains a higher percentage of larger pores (Bansal and Goyal 2005).
Beyond these, the other two commonly used activated car- bons are (i) commercial activated carbons and (ii) activated carbons prepared from agricultural waste materials.
Commercial activated carbons
Commercial activated carbons for the adsorption of CR have been extensively studied by (Kannan and Meenakshisundaram (2002), Fu and Viraraghavan (2002), Mall et al. (2005), Basava Rao and Ram Mohan Rao (2006), Lorenc-Grabowska and Gryglewicz (2007), Purkait et al. (2007), Zhang et al. (2007), Belhachemi and Addoun (2012), Abbas et al. (2012a), Rajappa et al. (2014a, b, c, d) and Singh et al. (2013). The adsorption capacities of various commercial activated carbons are reported in Table 2.
Commercial activated carbon is one of the best adsorbent for effluent treatment containing dyes (Gupta et al. 2009), but their use is sometimes restricted due to higher cost. In addi- tion, the CACs after their use become exhausted and are no longer capable of further adsorbing the dyes. Once CAC has been exhausted, it has to be regenerated by any one of the methods, like thermal, chemical, oxidation and electrochemi- cal regeneration, but again this whole process of regeneration adds additional cost; furthermore, any regeneration process results in reduction of adsorption capacity (Zhou and Lei 2006). This has led many workers to search for other alterna- tive adsorbents to commercial activated carbon which is discussed below.
Activated carbons prepared from agricultural and industrial solid wastes
Biomass and other waste materials have meager or no eco- nomic value and often create disposal problem; hence, it can be used as an inexpensive and additional renewable source of activated carbon. Thus, conversion of these low-cost by-prod- ucts into activated carbon would provide an inexpensive alter- native to the existing CACs, add economic value and help in reducing the cost of waste disposal.
An inexpensive and more easily available adsorbent would make the removal of pollutants an economically feasible option. Namasivayam and Kavitha (2002) stated that coir pith, agricultural wastes discarded in India, constitutes as much as
70 % of the coconut husk. It is a light fluffy material that is generated in the separation process of the fiber from the coco- nut husk. It is discarded as waste and its accumulation around coir processing centers is creating a nuisance. Thus, they uti- lized this waste material as an adsorbent for the removal of CR dye.
Similarly, a wide variety of carbon is processed from agri- cultural waste materials and used for the adsorption of CR from solution which includes bamboo dust carbon, coconut shell carbon, groundnut shell carbon, rice husk carbon, straw carbon (Kannan and Meenakshisundaram 2002), fertilizer plant waste (Mall et al. 2006), bael shell carbon (Ahmad and Kumar 2010), Myrtus communis and pomegranate (Ghaedi et al. 2012b). Table 3 presents the maximum adsorption ca- pacities of agricultural and industrial solid waste-based acti- vated carbons for CR. Table 4 is related with the nanoparticle- loaded activated carbon used for the adsorption of CR and their isotherm, kinetic and thermodynamic data including op- timal adsorption parameters.
Non-conventional low-cost adsorbents
A commonly used adsorbent, activated carbon (commercial and that derived from solid wastes), has a high capacity for the removal of CR dye from aqueous medium. But the extensive use of AC increases the cost of the wastewater treatment due to its disadvantages such as high cost of treatment and diffi- culty in regeneration. In addition, the adsorption capacity of varied carbon depends upon the sources of the raw material used, its preparation method and treatment conditions. Thus, it is a necessity to discover other inexpensive adsorbents which are easily available and are prepared without any addition of harsh chemical reagents. As a result of this, the adsorption process will become economically viable and environmental- ly benign.
Low-cost adsorbents (LCAs) are either prepared from nat- ural or industrial waste materials/by-products or from some synthetic materials.
There are several advantages associated with the use of LCAs such as low raw material cost because wastes are being utilized, abundant availability since the wastes are being pro- duced in large quantities and thus freely accessible as well as sustainability due to utilization of renewable resources.
Waste materials from agriculture and industry
Agricultural solid wastes Agricultural solid waste materials are available in large quantities and can be used as sorbents due to their physico-chemical characteristics and low cost. The utilization of agricultural solid wastes is of great signifi- cance and can play an important role in the national economy (Crini 2006).
Table 2 Maximum adsorption capacities of commercial activated carbon for CR
Wójtowicz (2013)
(2002)
18.ACL
19.ACC
20.Activated carbon
21.Activated carbon
Namasivayam and Kanchana (1993) investigated that ba- nana pith, which is the white central portion of the banana stem, also used to treat a person bitten up by a poisonous snake (Pushpangadan et al. 1989), is being used to remove CR from aqueous solution. The maximum adsorption capacity was 20.29 mg/g. The removal of dye by banana pith is mostly due to chemisorption. They concluded that the wastewater after treatment can be used for irrigation purposes mainly because it is rich in macro- and micro-nutrients due to the extract of banana pith.
Orange peel is discarded in the orange juice and soft drink industries all over the world. It has been used as an adsorbent for the removal of CR from wastewater by Namasivayam et al. (1996). The parameters which have an effect on waste- water treatment, such as dye concentration, agitation time, adsorbent dosage and pH, were investigated in batch-mode adsorption studies, and the results revealed that the equilibri- um time for CR removal was 90 min, maximum colour re- moval obtained was 92.0 % for an adsorbent dosage of 0.5 g for a dye concentration of 60 mg/L, adsorption followed both Langmuir and Freundlich isotherms and the adsorption capacity was 22.4 mg/g at pH 5.0. Further optimum pH for desorption was 12.0. Annadurai et al. (2002) used cellulose- based wastes (banana peel and orange peel) as an adsorbent and concluded that banana peel was more effective than or- ange peel for the removal of CR.
Rice husk is an agricultural waste and a by-product of the rice milling industry. It contains abundant floristic fiber, pro- tein and some functional groups such as carboxyl, hydroxy, amidogen, etc., which make the adsorption processes possi- ble. Furthermore, the yield of rice husk obtained from agricul- ture as a by-product is vast. Hence, the utilization of this source of agricultural waste would solve both disposal prob- lems well as access to a cheaper material for adsorption in a water pollutant control system.
A study by Han et al. (2008) reported about the removal of CR from aqueous solutions onto rice husk in column mode. The maximum adsorption capacity was obtained at pH 3.0 (tested pH range 3.0–6.0). The biosorption of CR was depen- dent on the flow rate, the inlet CR concentration and bed depth. The BDST model adequately described the adsorption of CR onto rice husk by column mode.
Other solid wastes from cheap and readily available re- sources such as biogas waste slurry (Namasivayam and Yamuna 1992), treated and untreated sunflower stalks (Shi et al. 1999), rice hull ash (Chou et al. 2001), Azadirachta indica leaf powder (Bhattacharyya and Sharma 2004), tama- rind fruit shell (Reddy 2006), neem leaves (Raghuvanshi et al. 2008), bottom ash and de-oiled soya (Mittal et al. 2009), tendu waste (Nagda and Ghole 2009), palm kernel seed coat (Oladoja and Akinlabi 2009), pyrolusite reductive leaching residue (Shen et al. 2014), rice husk ash (Chowdhury et al. 2009), date palm leaf base (Alsenani 2014), carbon slurry
Table 3 Maximum adsorption capacities of activated carbons derived from various agricultural and industrial solid wastes for CR
Sr. no. Adsorbents Adsorption capacity, qmax (mg/g)
Isotherm study
Kinetic study Thermodynamic
study
pH Initial dye concentration (mg/L)
Equilibrium time
Dosage of adsorbent References
1.Straw carbon [SC] 403.7 Freundlich Pseudo-1st-order – 7.4 175 120 min – Kannan and
Meenakshisundaram (2002)
2.Rice husk carbon [RHC]
3.Fertilizer plant waste carbon
4.Coconut shell carbon [CSC]
5.Grapefruit peel carbon (GPC)
6.AC produced from olive stones (OSAC)
7.GPAC
237.8 Freundlich Pseudo-1st-order – 7.4 175 120 min – Kannan and
Meenakshisundaram (2002)
m
8.Ground nut shells charcoal [GNC]
9.Groundnut shell carbon [GNSC]
10.Activated carbons prepared from date pits
11.Bamboo dust carbon [BDC]
105.00 Langmuir and R-P
Pseudo-2nd-order – 5.5–
6.5
Meenakshisundaram (2002)
100 24 h 10 mg/10 mL Belhachemi and Addoun (2012)
am
12.Bael shell carbon [BSC]
13.Neem sawdust carbon (NSDC)
14.GPUC
15.Eichhornia charcoal [EC]
16.Water nut-modified carbon (WNMC)
17.M2 (ACs prepared from the seeds of Martynia annua L. using H3PO4 as chemical activating agents)
(2010)
eco-friendly low-cost carbon prepared from
marine algae Valoria bryopsis
et al. (2006)
Environ Sci Pollut Res
waste (Bhatnagar et al. 2005), hen feather (Mittal et al. 2014), jute stick powder (Panda et al. 2009), wheat bran and rice bran (Wang and Chen 2009a), water hyacinth roots (Rajamohan 2009), rice husk ash (Chowdhury et al. 2009), cattail root (Hu et al. 2010), Alternanthera bettzichiana plant powder (Patil and Shrivastava 2010), ethylenediamine-modified wheat straw(Wang et al. 2011b), ball-milled sugarcane ba- gasse (Zhang et al. 2011), magnetically modified spent coffee grounds (Safarik et al. 2011), jujube seeds IJS (Zizyphus mauritiana) (Somasekhara Reddy et al. 2012), raw pine and acid-treated pine cone powder (Dawood and Sen 2012), pea- nut shell (Abbas et al. 2012b), cashew nut shell (Ponnusamy and Subramaniam 2013), eucalyptus wood (Eucalyptus globulus) sawdust (Mane and Vijay Babu 2013), Bengal gram fruit shell (Sivarama Krishna et al. 2014), rubber seeds (Zulfikar et al. 2014), chir pine (Pinus roxburghii) sawdust (Khan et al. 2014), Moringa oleifera seed cake powder (Tie et al. 2014), date palm leaf base (Alsenani 2014) and tea waste (Foroughi-dahr et al. 2015c) have also been successfully employed for the removal of CR from aqueous solution (Table 5).
Industrial by-products/industrial solid wastes Industrial by-products such as metal hydroxide sludge, fly ash, red mud, bio-solids and waste slurry can be used as low-cost ad- sorbents for CR removal. Table 6 represents the maximum adsorption capacities together with the optimized adsorption parameters as well as isotherm, kinetics and thermodynamics results of various industrial solid wastes for CR.
Metal hydroxide sludge —Golder et al. (2006) investigated the potential of electrocoagulated metal hydroxide sludge (EMHS) for adsorption of CR from aqueous solution. EMHS is generated during removal of heavy metals by electrocoagulation. They reported the maximum adsorption capacity of 513 mg/g at initial pH 3.0.
Attallah et al. (2013) studied the use of metal hydroxide sludge (MHS) generated from hot dipping galvanizing plant for adsorption of CR, and the adsorption capacity and percent- age of removal at pH 6.0 were 40 mg/g and 93 %, respectively. Wet palm oil milling is a common process of extracting palm oil and requires excessive amounts of steam and water. About 5–8 tonnes of water is utilized for every tonne of crude palm oil produced, to which more than 50 % of this water ends up as palm oil mill effluent (POME). Therefore, Zaini et al. (2013) utilized this palm oil mill effluent (sludge) as an adsor- bent for the removal of methylene blue dye. Similarly, this type of waste sludge can be employed as adsorbent for the
removal of CR dye.
Fly ash —Fly ash is defined as the particles that rise from thermal power plants when coal and lignite are burned for the production of electrical energy. The main components of
fly ash are alumina, silica, calcium oxide, iron oxide and re- sidual carbon (Bayat 2002). The estimated global production of fly ash was 67.5 million tonnes per year in 2010. It may be used in the construction of roads, bricks, cement, etc. It may also contain some hazardous materials, such as heavy metals. However, bagasse fly ash generated in the sugar industry does not contain large amounts of toxic metals and has been widely used for adsorption of CR.
Mall et al. (2005) used bagasse fly ash (BFA), generated as a waste material from bagasse field boilers, as an adsorbent for the removal of CR from aqueous solutions. Maximum adsorp- tion capacity for CR was reported as 11.89 mg/g (at pH 7.0 and adsorbent dosage of 1.0 g/L), and the equilibrium time of adsorption was achieved within 4 h of contact.
Acemioğlu (2004) investigated the use of calcium-rich fly ash for the adsorption of Congo red from solution with differ- ent contact times, concentrations, temperatures and pH values. The adsorption equilibriums have been described in terms of both the Freundlich and Dubinin-Radushkevich models. The author reported that the adsorption process obeyed the pseudo-second-order kinetic model. The enthalpy of adsorp- tion was found to be 27.13 kJ/mol. This indicated that most of the dye was held by fly ash via chemisorption as well as ion exchange.
Waste red mud —Red mud (bauxite wastes of alumina man- ufacture) appears as unwanted by-products during alkaline leaching of bauxite in the Bayer process, which is used for the production of alumina from bauxite.
Waste red mud was used as adsorbent for the sequestration of CR from wastewater by Namasivayam and Arasi (1997). For this purpose, batch adsorption experiments were applied changing the solution pH (2.0–11.0), initial adsorbate concen- tration (10–40 mg/L) and contact time (10–180 min). Optimum conditions were found to be at pH 2.0, 90 min of contact time and 10 mg/L of initial dye concentration. The adsorption process followed the Langmuir and Freundlich isotherms and the Langmuir adsorption capacity was
4.05mg/g.
The removal of CR from synthetic wastewater by using activated red mud was investigated by Tor and Cengeloglu (2006). It was reported that maximum CR removal occurred at pH 7.0 after 90 min of contact time. The adsorption iso- therms were analysed using the Langmuir, the Freundlich and the three-parameter Redlich-Peterson isotherms. Based on the non-linear chi-square statistic test, it was found that adsorption fitted well to the Langmuir model than the other two models.
Natural materials
Clays Clay is a mineral composed of alumina and silica that usually includes bound water. Clays have a sheet-like struc- ture and are composed of tetrahedrally arranged silicates and
Table 4 Maximum adsorption capacities of nanoparticle-loaded activated carbon for CR
Sr.
no.
Adsorbents Adsorption
capacity,
qmax (mg/g)
Isotherm study
Kinetic study Thermodynamic study
pH Initial dye concentration (mg/L)
Equilibrium time
Dosage of adsorbent
References
1.Activated carbon/surfactant (AC/DDAC)
2.Tin sulfide nanoparticles
loaded on AC (SnS-NP-AC)
3.Nickel-doped zinc sulfide
nanoparticle loaded on AC (Ni-ZnSNP-AC)
4.Zinc oxide nanorods loaded on AC (ZnO-NRs-AC)
5.Palladium nanoparticles loaded on AC (Pd-NPs-AC)
6.Palladium nanoparticles loaded on AC (Pd-NPs-AC)
769.48 Langmuir Pseudo-2nd-order Endothermic 3.5 160 100 min 20 mg Cheng et al. (2015)
384.60 Langmuir Pseudo-2nd-order – 1.0 15.0 4.0 min 0.03 g Dehghanian et al. (2015)
285.70 Langmuir Pseudo-2nd-order – 3.0 40.0 25.0 min 0.03 g Ahmadi et al. (2014)
142.9 Langmuir Pseudo-2nd-order Endothermic 7.0 25.0 7.0 min 0.02 g/L Ghaedi et al. (2012a)
126.60 Langmuir Pseudo-2nd-order – 2.0 40.0 26.0 min 0.04 g Ahmadi et al. (2014)
76.9 Langmuir Pseudo-2nd-order Endothermic 6.0 25.0 24.0 min 0.02 g/L Ghaedi et al. (2012a)
7.Gold nanoparticle-loaded AC 71.43 Langmuir Pseudo-2nd-order Endothermic 4.0 15.0 15.0 min 0.025 g Ghaedi et al. (2011)
8.AuNPs-coated AC 71.05 Freundlich Pseudo-1st-order – 6.5 ± 0.8 2.0 270 min 7.0 g/100 mL Pal and Deb (2014)
9.Silver nanoparticles loaded on AC (AgNPs-AC)
66.7 Langmuir Pseudo-2nd-order Endothermic 4.0–7.0 25.0 14.0 min 0.02 g/L Ghaedi et al. (2012a)
10.AgNPs-coated AC 64.80 Freundlich Pseudo-1st-order – 6.5 ± 0.8 2.0 270 min 7.0 g/100 mL Pal and Deb (2014)
Table 5 Maximum adsorption capacities of agricultural solid wastes for CR
7. Hen feather 73.84 Langmuir, Freundlich, Tempkin and D-R
Pseudo-2nd-order Endothermic 7.0 10 × 10−5 M 3.0 h 0.070 g/25 mL Mittal et al. (2014)
acquired/ discharged
by the adsorption was negligible
Table 5 (continued)
Sr. no. Adsorbents Adsorption capacity, qmax Isotherm study Kinetic study Thermodynamic study pH Initial dye concentration Equilibrium time Dosage of adsorbent References
(mg/g) (mg/L)
21. Sugarcane bagasse 38.20 Freundlich Pseudo-2nd-order Exothermic 5.0 500.0 120 min 5.0 g/L Zhang et al. (2011)
22. Sunflower stalks 37.78 Langmuir – – – – – – Sun and Xu (1997)
23. Jute stick powder 35.70 Langmuir Intra-particle – 6.0 50.0 180 min 0.5 g/50 mL Panda et al. (2009)
24.
Untreated sunflower stalks
34.26
Langmuir diffusion Pseudo-1st-order
Endothermic
–
–
–
–
Shi et al. (1999)
29.SP (Bengal gram fruit shell)
30.Rice hull ash/kaolinite/starch
Shojamoradi et al. (2013)
Foroughi-dahr et al. (2015c)
Wang and Chen (2009a)
Namasivayam et al. (1996)
22.22 Langmuir Pseudo-2nd-order Endothermic 5.0 100.0 300 min 4.0 g/L Sivarama Krishna
et al. (2014) 21.00 – – – – – – – Shi et al. (1999)
31.Waste banana pith 20.29 – Pseudo-1st-order – 8.97 100.0 140 min – Namasivayam and
Kanchana (1993)
32.Raw pine cone 19.18 Freundlich Pseudo-2nd-order Endothermic 3.55 20.0 140 min 20 mg/50 mL Dawood and Sen
(2012)
33.Pigeon dropping 18.45 Langmuir Pseudo-2nd-order Exothermic 6.3 125.0 60 min 0.2 g Kaur et al. (2014)
34.Banana peels 18.20 Freundlich Intra-particle
diffusion
– 6.0–7.0 100.0 65 min 1.0 g/L Annadurai et al.
(2002)
35.Peanut shell 15.09 Langmuir – Exothermic – – – – Abbas et al. (2012b)
36.Alternanthera bettzichiana plant powder
14.67 Langmuir and Freundlich
Pseudo-2nd-order – 5.0 20.0 130 min 2.0 g/L Patil and Shrivastava
(2010)
d Chen (2009a)
i et al.
Freundlich
Table 5 (continued)
Sr. no. Adsorbents Adsorption capacity, qmax (mg/g)
Isotherm study Kinetic study Thermodynamic
study
pH Initial dye concentration (mg/L)
Equilibrium time
Dosage of adsorbent References
45.Magnetically modified
spent coffee grounds
9.42 Langmuir – – – – 90 min – Safarik et al. (2011)
46.Soil (30 °C) 8.65 Freundlich Pseudo-2nd-order Exothermic 6.8–6.9 100.0 40 min 2.5 g/50 mL Smaranda et al. (2010)
47.Risk husk ash 7.047 Freundlich Pseudo-2nd-order – Natural 125.00 60 min 80.0 g/L Chowdhury et al.
(2009)
48.Chir pine (Pinus roxburghii) sawdust (CPS)
5.80 Freundlich Pseudo-1st-order Endothermic 2.0 175.00 60 min 30.0 g/L Khan et al. (2014)
49.Cashew nut shell 5.184 R-P Pseudo-2nd-order Exothermic – 50.0 2.0 h 20.0 g/L Senthil Kumar et
al. (2010)
50.Paddy straw 1.01 – – – – – – – Deo and Ali (1993)
51.Sawdust 0.402 Langmuir Pseudo-2nd-order Endothermic 9.0 50.0 120 min 3.0 g/150 mL Nimkar and Chavan
(2014)
52.Low-cost adsorbent 0.150 Freundlich – – – – – – Baitod et al. (2015)
53.Activated de-oiled mustard (ADM)
120.35 (mol/g) Langmuir Pseudo-1st-order Endothermic 6.5 1.0 × 10−4
mol/dm3
– 0.26 g/L Jain and Sikarwar (2014)
54.Date palm leaf base 0.20 × 10−4
(mol/g)
55.Moringa oleifera seed –
cake powder (MOSCP)
56.Tea waste (TW) –
(2015b)
57.Cationic
surfactant-modified
– – – – – – – – Zhao et al. (2014a)
wheat straw
58.Rice husk – – – – – – – – Han et al. (2008)
59.Cashew nut shell – – – – 3.2 20.0 67 min 24.76 g/L Ponnusamy and
Subramaniam (2013)
60.Rice husk ash (RHA)
– Langmuir – – 4.0 – – 80.0 g/L Sarkar and
Bandyopadhyay (2010)
Table 6 Maximum adsorption capacities of industrial by-products/industrial solid wastes for CR
Sr.
no. Adsorbents Adsorption capacity, Isotherm study Kinetic study Thermodynamic study pH Initial dye concentration Equilibrium time Dosage of adsorbent References
qmax (mg/g) (mg/L)
1. EMHS 293.00 Langmuir – Endothermic 7.0 100 60 min 0.2 g/250 mL Golder et al. (2006)
2. Carbon slurry waste 272.00 Langmuir – Exothermic 5.5–
6.5 – 2.0 h 0.01 g/10 mL Bhatnagar et al. (2005)
3.Rice hull ash 171.00 Langmuir – – – – – – Chou et al. (2001)
4.Physical activated bottom ash
106.61 Freundlich – – – – 24 h – Saleh et al. (2012)
models
Environ Sci Pollut Res
octahedrally arranged aluminates. Due to their low cost, abun- dance in nature, high sorption capacity and potential for ion exchange, clay minerals are frequently used as an adsorbent. Clay minerals always contain exchangeable ions on their sur- face and play a vital role in the environment by acting as natural scavengers of contaminants by taking up cations and/ or anions through either ion exchange or adsorption (Babel and Kurniawan 2003).
Though natural clay minerals weakly adsorb acidic con- taminants due to the repulsive force between the anion and the negative charge on the surface of the clay (Ghosh and Bhattacharyya 2002), there are also various modified clay minerals used for the adsorption of CR, an anionic dye.
A number of natural and modified clay minerals such as raw clay (Ghribi et al. 2014), open burnt clay (Mumin et al. 2007), Australian kaolin clay (Vimonses et al. 2009b), montmorillonite (Yermiyahu et al. 2003; Wang and Wang 2007a), bentonite (Bulut et al. 2008; Akl et al. 2013), Ca-bentonite (Lian et al. 2009a), Na-bentonite (Vimonses et al. 2009c), kaolin (Vimonses et al. 2009c; Zenasni et al. 2014) and zeolite (Vimonses et al. 2009c) have been investigated for CR removal. Compared to natural clay minerals, modified clay minerals show a strong affinity for the anionic dye Congo red (shown in
Table 7).
Kaolin or china clay has received considerable attention as an adsorbent because of its high adsorption capacity. It is commonly referred to as clay that consists mainly of kaolinite and a lower amount of minerals such as quartz and mica. Vimonses et al. (2009b) tested the ability of three Australian kaolin clays (Q38, K15GR and Ceram) for remov- ing CR from aqueous solutions. The dye uptake process obeyed the pseudo-second-order kinetic expression and was best described by the Langmuir isotherm. Thermodynamic studies showed that CR adsorption on all kaolins was exother- mic and spontaneous in nature.
Siliceous materials The natural siliceous materials used for CR adsorption are perlite, silica, glass fibers, alunite and do- lomite because of their high abundance, easy availability and low cost.
Perlite is defined as a naturally occurring glassy volcanic siliceous rock. It has high silica content, greater than 70 %. Vijayakumar et al. (2009) studied the removal of CR from aqueous solution by perlite. They reported that 40 min of con- tact time, 0.1 g/50 mL of adsorbent dosage and 3–4 pH value were optimum conditions for the removal of CR. It was sug- gested that the adsorption of CR onto perlite was spontaneous, chemical and exothermic in nature and followed the Langmuir isotherm as well as the pseudo-second-order kinetic rate model.
Zeolites Zeolite is a crystalline mineral with a structure char- acterized by a framework of linked tetrahydrals, each consisting of four oxygen atoms surrounding a cation. This
framework contains open cavities in the form of channels and cages. They are occupied by water molecules and extra frame- work cations that are commonly exchangeable and are large enough to allow the passage of guest species. The important properties of zeolite such as relatively high specific surface areas, high ion-exchange capacity and low cost make them attractive adsorbents (Babel and Kurniawan 2003).
Vimonses et al. (2009c) stated that the increase in the ad- sorption capacity of zeolites at acidic pH may relate to the increased complexity of zeolite channels. As shown in Table 7, the removal efficiency of zeolites for CR may not be as good as that of clay materials. However, their easy avail- ability and low cost may compensate for this limitation.
Biosorbents
Biosorption is defined as the accumulation and concentration of pollutants from aqueous solutions by the use of biological materials. Biological materials such as biopolymers, yeast, fungi or bacterial biomass are used as adsorbents for the re- moval of CR from aqueous media.
Biomass Decolorization/bioadsorption of CR dye from waste- water by (dead/living) biomass (Fu and Viraraghavan 2002), biomass of white-rot fungi (Selvam et al. 2003; Binupriya et al. 2008; Yang et al. 2011) and algae (Wang and Chen 2009b) was studied by many researchers (shown in Table 8). Fu and Viraraghavan (2002) concluded that compared with the GAC and PAC, dead fungal biomass of Aspergillus niger is a promising biosorbent for CR removal. Pretreatment of fungal biomass with NaHCO3 was found to be the most effective one for CR removal. Experimental results showed that effective initial pH was 6.0 and equilibrium time was 42 h. According to the Langmuir equation, the maximum
uptake capacity for CR was 14.16 mg/g.
Binupriya et al. (2008) reported the adsorptive removal of CR by the white-rot fungi Trametes versicolor. Living and dead fungal biomass after various pretreatments were being used. The results revealed that the adsorption was found to be pH dependent and follow the Langmuir adsorption isotherm which suggested that the sorption was monolayer coverage. Selvam et al. (2003) also reported the usefulness of biomass white-rot fungus Thelephora sp. for the decolorization of CR.
The major problem encountered during the use of biomass is that the biosorption process is slow, and in case of biomass of A. niger, the equilibrium was reached in 42 h. In addition, the initial pH of the dye solution significantly influenced the bioadsorption.
Wang and Chen (2009b) investigated the removal of CR from aqueous solution by using the non-living biomass of Porphyra yezoensis Ueda (red alga). Langmuir and Freundlich equations were applied to the data related to the adsorption isotherms. The results showed that adsorption of
Table 7 Maximum adsorption capacities of natural materials for CR
Sr.
no. Adsorbents Adsorption capacity, Isotherm study Kinetic study Thermodynamic study pH Initial dye concentration Equilibrium time Dosage of adsorbent References
qmax
(mg/g) (mg/L)
1. Calcinated clay materials 666.67 Freundlich Pseudo-2nd-order – – 150.0 150 min 1.0 g/L Vimonses et al.
and lime (2010)
2.Clay mixture >575 Langmuir Pseudo-2nd-order – – 600.0 150 min 1 g/L Vimonses et al.
(2009a)
3.Ag-modified calcium
hydroxyapatite [Ag (10): CaHAp]
4.Cetyltrimethylammonium bromide-modified montmorillonite (CTAB-MMT)
5.Cetyltrimethylammonium bromide-montmorillonite (CTAB-MMT)
554.54 Langmuir Pseudo-2nd-order – – 50–300 10 h 1 g/L Srilakshmi and
Saraf (2016)
351.00 Langmuir Pseudo-2nd-order Endothermic 7.5 1100 480 min 0.05 g/25 mL Wang and Wang
(2008a)
229.00 Langmuir Pseudo-2nd-order Endothermic 7.5 – – – Wang and Wang
(2008b)
10.Surfactant-modified
zeolites (SMZs)
11.Bentonite
12.Organified rectorite
(CTA+-REC)
13.Stearyltrimethylammonium
by combined acid and thermal activation (ATA)
(2012)
Table 7 (continued)
Sr.
no. Adsorbents Adsorption capacity, Isotherm study Kinetic study Thermodynamic study pH Initial dye concentration Equilibrium time Dosage of adsorbent References
qmax
(mg/g) (mg/L)
18. Kaolin-bentonite clay 71.43 Langmuir Pseudo-2nd-order Exothermic 10.0 100.0 80 min 0.1 g Ogunmodede et al.
(KBC) (2015)
19. Natural bentonite modified 69.44 Freundlich Pseudo-2nd-order Exothermic 7.0 1000.0 4.0 h 20.0 g/L Toor and Jin
by acid activation (AA) (2012)
20. Perlite 55.55 Langmuir Pseudo-2nd-order Exothermic 3.0–4.0 40.0 40 min 0.1 g/50 mL Vijayakumar et al.
(2009)
21. Natural bentonite modified 54.64 by thermal activation Freundlich Pseudo-2nd-order Exothermic 7.0 1000.0 4.0 h 20.0 g/L Toor and Jin (2012)
(TA)
22. Burnt kaolinitic clay 45.893
Langmuir and
–
–
5.0–9.0
40.0
60 min
0.25 g/50 mL
Nwokem et al.
Freundlich (2012)
23. Bentonite 40.40 Langmuir Pseudo-2nd-order Endothermic 5.0–9.0 300.0 120 min 0.1 g/50 mL Akl et al. (2013)
24. Iron-grafted clinoptilolites 36.70 Langmuir – Endothermic 6.3 200.0 30 min – Akgül (2014)
(Fe-CL)
25. Sodium bentonite 35.84 Freundlich Pseudo-2nd-order Exothermic 7.5 ± 0.3 150.0 – 20 g/L Vimonses et al. (2009c)
26. Octyltrimethylammonium 31.10 – – – – – – – Wang and Wang
bromide-montmorillonite (2008b)
(OTAB-MMT)
27. Raw clay 27.03 Langmuir Pseudo-2nd-order – 7.5 ± 0.2 50.0 200 min 1.0 g/100 mL Ghribi et al.
(2014)
28. Cetyltrimethylammonium 24.46 Langmuir Pseudo-2nd-order – 6.9 100.0 40 min 0.1 g/10 mL Zenasni et al.
bromide-modified kaolin (2014)
(CTAB-kaolin or KC)
29. Open burnt clay 22.86 Langmuir and Pseudo-1st-order – 3.0 50.0 300 min 0.5 g/200 mL Mumin et al.
Freundlich (2007)
30. Raw rectorite (R-REC) 19.50 Langmuir Pseudo-2nd-order Exothermic 7.0 500.0 3000 min 0.025 g/25 mL Liu et al. (2010)
31. Raw clinoptilolites (Ra-CL) 16.90 Langmuir – Endothermic 6.3 200.0 30 min – Akgül (2014)
32. Montmorillonite 12.70 Langmuir Pseudo-2nd-order – 7.0 25–100 120 min 0.1 g/25 mL Wang and Wang
(2007a)
33. Australian kaolin clay 7.27 Langmuir Pseudo-2nd-order Exothermic 7.5 ± 0.3 250.0 – 20.0 g/L Vimonses et al.
Ceram (2009b)
34. Australian kaolin clay 6.81 Langmuir Pseudo-2nd-order Exothermic 7.5 ± 0.3 200.0 – 50.0 g/L Vimonses et al.
K15GR (2009b)
35. Natural kaolin (K) 5.94 Langmuir Pseudo-2nd-order – 6.9 100.0 40 min 0.1 g/10 mL Zenasni et al.
(2014)
Environ Sci Pollut Res
CR followed the pseudo-second-order kinetics and the maxi- mum adsorption capacity was 71.46 mg/g at 25 °C.
Biopolymers Biopolymers are high molecular weight com- pounds synthesized by living organisms. Since they are poly- mers, they contain monomeric units that are covalently bond- ed to large structures. Because of this, biopolymers can be used as adsorbents for the efficient removal of hazardous dyes. Chitin and chitosan are significantly adaptable and promising biopolymers. Chitin (poly[β-(1→4)-2-acetamido-2-deoxy-β- D-glucopyranose]), a polymer of N-acetyl-D-glucosamine, is the second most plentiful biopolymer after cellulose on earth and is widely distributed in nature, especially in the exoskel- etons of marine invertebrates such as shrimps, crabs, prawns and lobsters. Chitosan (poly[β-(1→4)-2-amino-2-deoxy-β-D- glucopyranose]), a hetero-polysaccharide of D-glucosamine and N-acetyl-D-glucosamine residues, is obtained by the alka- line deacetylation of chitin (Gamage and Shahidi 2007). Both these biopolymers exhibit a high adsorption capacity towards dyes due to their multiple functional groups, biocompatibility, biodegradability and non-toxicity (Ravi Kumar 2000).
The performance of chitosan as an adsorbent to remove CR has been demonstrated by Wang and Wang (2007a). They found that the maximum adsorption capacity of chitosan pow- der for CR was 74.73 mg/g. However, the bead type of chito- san gives a higher adsorption capacity (93.71 mg/g) than flake or powder type as reported by Chatterjee et al. (2007). This can be explained by the fact that the beads possessed a greater surface area than the flakes.
In an effort to increase the efficiency of chitosan, it has been modified or crosslinked with various surfactants and crosslinking agents as shown in Table 9.
Peat Peat is a porous and complex natural material, widely available and studied as an alternative adsorbent for different pollutants as well as dyes. Peat is classified into four groups, namely moss peat, herbaceous peat, woody peat and sedimen- tary peat based on the nature of parent materials. Peat is abun- dant in nature and a relatively inexpensive biosorbent. The major constituents of raw peat are lignin, cellulose and fulvic and humic acid. These constituents, especially lignin and hu- mic acid, bear polar functional groups, such as alcohols, alde- hydes, ketones, carboxylic acids, phenolic hydroxides and ethers that can be involved in chemical bonding (Sun and Yang 2003).
Zehra et al. (2015) used peat as an adsorbent without any pretreatment for studying the adsorption of CR on it. The authors studied the changes in the structure and surface of peat by using scanning electron microscopic and X-ray fluores- cence techniques. The adsorption capacity under optimized conditions of shaking time (1.5 h), settling time (0.5 h) and medium pH (6.4) was determined to be 10.1 mg/g at equilib- rium. The adsorption process follows monolayer adsorption
Table 8 Maximum adsorption capacities of biomass (living/dead) adsorbents for CR
Sr.
no. Adsorbent Adsorption capacity, qmax Isotherm study Kinetic study Thermodynamic study pH Initial dye concentration Equilibrium time Dosage of adsorbent References
(mg/g) (mg/L)
1. Non-viable Penicillium 411.53 Langmuir Pseudo-2nd-order Endothermic 3.0 800.0 – 0.1 g/100 mL Yang et al. (2011)
YW 01 biomass
2. Microalga Chlorella 202.9 Langmuir – – – 5.0–25.0 72 h – Hernández-Zamora
vulgaris et al. (2015)
3. Spent mushroom (SM) 147.10 Langmuir Pseudo-2nd-order – 5.0 350–450 180 min 4.0 g/L Tian et al. (2011)
(Tricholoma lobayense)
4. L. edodes immobilized 143.678 Freundlich Pseudo-2nd-order – 5.0 – 12.0 h – Gimenez et al. (2014)
on loofa sponge
5. Lentinus edodes 131.926 Freundlich Pseudo-2nd-order – 5.0 – 12.0 h – Gimenez et al. (2014)
6. Cicerarientinum crop 99.01 Langmuir Pseudo-2nd-order Exothermic 2.0 20.0 35 min 2.5 g Jirekara and
seeds Farooquib
(2015)
7. Magnetic Saccharomyces 93.10 Langmuir – – – – – – Šafaříková et al.
cerevisiae subsp. (2005)
Uvarum
8. Biomass of P. yezoensis 71.46 Langmuir Pseudo-2nd-order – 8.0 80.0 600 min 5.0 g/L Wang and Chen
Ueda (2009b)
9. Novel magnetic Rhizopus 65.19 Langmuir Pseudo-2nd-order – – – – 1.0 g/L Fu et al. (2015)
oryzae biomass
particles
(m-RBps)
10. Biomass of Trametes 51.81 Langmuir and Pseudo-2nd-order – 7.0 10–50 65 min 1.5 g/50 mL Binupriya et al.
versicolor Temkin (2008)
11. Ferrofluid-modified 49.70 Langmuir – – – – – – Safarik et al. (2007)
fodder
yeast (Kluyveromyces
fragilis) cells
12. Dead fungus (Aspergillus 14.16 Radke- Pseudo-2nd-order – 6.0 50 42 h 0.2 g/75 mL Fu and Viraraghavan
niger) Prausnitz (2002)
13. Leucaena leucocephala 4.413 Langmuir Pseudo-2nd-order – 5.0 20.0 120 min 2.0 g/L Shrivastava (2012)
(Subabul) seed pods
14. Cassia fistula seeds ash 2.46 Langmuir Pseudo-2nd-order Exothermic 2.5 60.0 30 min 4.0 g/100 mL Kaur and Thakur
(2014)
15. Roots of Eichhornia 1.580 Langmuir Pseudo-2nd-order – – 104.45 90 min 1.5 g/50 mL Wanyonyi et al.
crassipes (2014)
16.Aloe barabadensis
Mill. extract
– – – Maximum
decoloration at 40 °C
6.0 – 2.0 h – Rai et al. (2014)
17.Loofa sponge – Freundlich Pseudo-2nd-order – 5.0 – 12.0 h – Gimenez et al. (2014)
18.White-rot fungus
Thelephora sp.
19.Baker’s yeast
(Saccharomyces cerevisiae) strain
– – – – – – – – Selvam et al. (2003)
– Freundlich – – Mahmoud (2015)
Table 9 Maximum adsorption capacities of biopolymers for CR
Sr. no. Adsorbents Adsorption capacity, qmax Isotherm study Kinetic study Thermodynamic study pH Initial dye concentration Equilibrium time Dosage of adsorbent References
(mg/g) (mg/L)
1. IPN of chitosan and 742.00 Langmuir Pseudo-2nd-order Endothermic 7.0 140 – 0.1 g/100 mL Mandal and Ray
(sodiumacrylate-co- (2014)
hydroxyethyl
methacrylate) [SCPCS]
2. Lignocellulose (LC) 622.70 Redlich-Peterson Pseudo-2nd-order Endothermic 4.29 28.5 Variable with 0.69 g/L Debnath et al.
initial dye (2015)
conc.
3.IPN of chitosan and poly(acrylic
acid-co-hydroxyethyl methacrylate) [CPCS]
4.Flower-like chitosan/calcium pyrophosphate hybrid microparticles (microflowers)
5.CS/CNT beads
6.CTAB-modified chitosan beads
7.CS beads impregnated with triton X-100 (TX-100) as a nonionic surfactant CS/TX-100 beads
d Ray
.
et al.
(2010b)
et al.
(2009a)
et al.
hydrogel beads (CSBs)
Table 9 (continued)
Sr. no. Adsorbents Adsorption capacity, qmax Isotherm study Kinetic study Thermodynamic study pH Initial dye concentration Equilibrium time Dosage of adsorbent References
(mg/g) (mg/L)
Chatterjee et al.
(2011b)
19. Chitosan-tripolyphosphate 166.66 Langmuir Pseudo-2nd-order – 6.0 140.0 90 min 100 mg/ Raval et al. (2015)
(CTS) beads 100 mL
20. CS fibers 144.93 Langmuir – – 5.0 20–200 600 min 0.9 g/L Du et al. (2014)
21. Glutaraldehyde cross-linked 125.00 Langmuir Pseudo-2nd-order – – 50.0 8.0 h 0.1 g/50 mL Feng et al. (2011)
chitosan film
22. Chitin (CH) beads 111.11 Langmuir Pseudo-2nd-order – 6.0 140.0 90 min 100 mg/ Raval et al. (2015)
100 mL
23. Chitosan beads 93.71 Langmuir Pseudo-2nd-order Exothermic 6.0 500.0 7.0 h 1.0 g Chatterjee et al.
(2007)
(2005)
(2013)
methacrylate) (ChgPMMA)
6.0
(2010)
Environ Sci Pollut Res
with small contribution to multilayer formation qualifying the validity of the Redlich-Peterson model, which is further sup- ported by error function determination. Kinetics studies were in agreement with the pseudo-second-order model and the adsorption reaction proceeds according to intra-particle diffusion.
Nanomaterials
In the past few decades, nanotechnology has developed in almost all branches of science and technology. In this progres- sion, treatment of contaminated water is not dispossessed of nanotechnology. Typical nanomaterials currently under explo- ration include nanoparticles, nanotubes, nanofibers, fullerenes and nanowires (Schmidt et al. 2002).
Nanostructured materials are noted for their stability and green chemistry and found to have diverse technical applica- tions (Bhushan 2010). Nano-sized materials are new function- al materials, which offer high specific surface area to volume ratio and surface active sites, and therefore, they can be used as efficient adsorbents. Furthermore, nanomaterials have been used in diverse environmental applications such as in photo- catalytic degradation of organic dye, remediation of polluted water, pollutant sensing and detection, antibacterial activity and so on. Because of such diverse utilizations of nanomaterials in a wide range of industries, the production of engineered nanomaterials is estimated to increase from 400 to 58,000 tonnes in 2011–2020 (Sharma 2009).
The particles of at least one dimension smaller than 1 μm and potentially as small as atomic and molecular length scales (0.2 nm) are called nanoparticles. Nanoparticles can have amor- phous or crystalline form (Buzea et al. 2007). Due to some of the unique characteristics such as small size, catalytic potential, large surface area, ease of separation and large number of active sites for interaction with different contaminants, nanoparticles have established themselves as excellent adsorbents.
The commonly used nanoparticles for water treatment are made of alumina, anatase, akaganeite, cadmium sulfide, co- balt ferrite, copper oxide, gold, maghemite, iron, iron oxide, iron hydroxide, nickel oxide, silica, stannous oxide, titanium oxide, titanium oxide, zinc sulfide, zinc oxide, zirconia and some alloys (Ali 2012).
Amongst all these nanoparticles, iron oxide nanoparticles have attracted the attention of researchers due to their excel- lent magnetic properties, high surface area, high adsorption capacity, nanoparticle size and easy magnetic separation of solids after adsorption (Giri et al. 2011). Magnetite (Fe3O4) and maghemite (γ-Fe2O3) are the common types of iron ox- ides used for the removal of CR due to their super-magnetic properties. The behavior of magnetic nanoparticles strongly depends on size, surface chemistry, state of aggregation and preparation methods.
Nanomaterials exhibit a strong affinity for CR and as well as it has relatively good capability for uptake of CR which has been demonstrated by many researchers (Table 10).
Nanocomposites
Composites and nanocomposites have attracted increasing re- search attention and have been frequently used as adsorbents for the treatment of wastewater.
Composites refer as the nano-scale inclusions that are im- bedded within the matrix of a material. The adsorption ability of composites relies on the smart manipulation of the structure of the embedded compounds such as charge, functionality, hydrophobic-hydrophilic nature, etc. (Chen et al. 2013c).
Nanocomposites refer to materials consisting of at least two phases in which one dispersed in another is called matrix and thus forms a three-dimensional network (Hussain et al. 2006). The properties of a nanocomposite are greatly influenced by the size scale of its component phases and even the degree of mixing between the two phases. Depending on the nature of the components used (layered silicate or nanofiber, cation ex- change capacity and polymer matrix) and the method of prep- aration, significant differences in composite properties may be obtained (Park et al. 2001).
Composites of polymers and inorganic materials are report- ed to provide many synergistic properties, which are arduous to attain from individual components (Riede et al. 2000). Hou et al. (2012) extend the use of hydroxyapatite/chitosan (HAp- CS) biocomposite for CR removal. The authors prepared the composite to improve the mechanical strength and adsorption efficiency of chitosan by immobilizing it on an inorganic ma- terial, hydroxyapatite [Ca10(PO4)6(OH)2, HAp], by the co- precipitation method.
Clay minerals have been adapted to the field of composites with polymers because of their small particle size and intercala- tion property (Agag and Takeichi 2000). Polymer/ montmorillonite nanocomposites have improved properties such as excellent mechanical properties, thermal stability, gas barrier and flame retardation in comparison to conventional composites (Zhao et al. 2010). Wang and Wang (2007a) developed a novel adsorbent chitosan/montmorillonite nanocomposite by control- ling the molar ratio of chitosan (CTS) and montmorillonite (MMT). The nanocomposites were characterized by FT-IR and XRD. Adsorption characteristics of the nanocomposite were ex- amined by using CR as an adsorbate. The outcomes indicated that the adsorption isotherm data were fitted well to the Langmuir isotherm and followed the pseudo-second-order kinet- ic model. The results signified that the adsorption capacity of the CTS/MMT nanocomposite (54.52 mg/g) was higher.
Other polymer/montmorillonite nanocomposites, i.e. chitosan/organo-montmorillonite nanocomposite (Wang and Wang 2007b), N,O-carboxymethyl chitosan montmorillonite nanocomposite (Wang and Wang 2008b), carboxymethyl
Table 10 Maximum adsorption capacities of nanomaterials for CR
nanoparticles and nanowhiskers
arrays (NWAs) bundles (NWBs)
Table 10 (continued)
arrays (NBAs)
26. Hierarchical porous bismuth oxyiodide (BiOI) architectures
216.80 Freundlich Pseudo-2nd-order – 5.0 60.0 90 min 0.02 g/50 mL Ai et al. (2014)
oxide (mixed γ-Fe2O3/Fe3O4
phase)
nanostructures (called u-MFN)
40. Fe2.95La0.05O4 107.64 Langmuir Pseudo-2nd-order – Natural 100.0 90 min 0.100 g/L Wang et al. (2011a)
41. FeC2O4⋅2H2O nanorod 103.09 Langmuir Pseudo-2nd-order – 5.0 100.0 30 min 0.05 g/20 mL Dhal et al. (2014)
42. FeFe2O4 97.429 – – – – 100.0 30 min 50 mg/50 mL Wang et al. (2012b)
43. NiFe2O4 97.10 Langmuir Pseudo-2nd-order – 7.0 150.0 40 min 0.015 g/50 mL Wang et al. (2012a)
44. Fe 95.773 – – – – 100.0 30 min 50 mg/50 mL Wang et al. (2012b)
Table 10 (continued)
Sr. Adsorbents Adsorption Isotherm study Kinetic study Thermodynamic pH Initial dye Equilibrium Dosage of References
no. capacity, study concentration time adsorbent
qmax (mg/g) (mg/L)
45. α-Fe2O3 hollow structures (FHSs) 93.546 Langmuir Pseudo-2nd-order – – – – – Wu et al. (2013)
46. MnFe2O4 92.40 Langmuir Pseudo-2nd-order – 7.0 150.0 40 min 0.015 g/50 mL Wang et al. (2012a)
47. Hierarchical spindle-like γ-Al2O3 90.00 Langmuir – – – – – – Cai et al. (2010)
48. K1.33Mn8O16@ α-Fe2O3 84.531 Langmuir Pseudo-2nd-order – – – – – Wu et al. (2013)
heterostructured nanowires (KFHWs)
49. Hierarchical Ni(OH)2 nanosheets 82.90 Langmuir Pseudo-2nd-order – 7.0 25.0 300 min 200 mg/L Cheng et al. (2011)
50. Magnetite nanoparticle-loaded 82.64 Langmuir Pseudo-1st-order – 6.0 20.0 35 min 0.04 g/20 mL Madrakian et al.
tea waste (MNLTW) (2012)
51. Hierarchical hollow MnO2 80.00 – – – – 100.0 – 0.03 g/20 mL Fei et al. (2008)
nanostructures
52. α-Fe2O3 nanorod 78.13 Langmuir Pseudo-2nd-order – 5.0 100.0 30 min 0.05 g/20 mL Dhal et al. (2014)
53. Palladium nanoparticles loaded 76.9 Langmuir Pseudo-2nd-order Endothermic 6.0 25.0 24.0 min 0.02 g/L Ghaedi et al.
on activated carbon (2012a)
(Pd-NPs-AC)
54. AuNPs-coated AC 71.05 Freundlich Pseudo-1st-order – 6.5 ± 0.8 2.0 270 min 7.0 g/100 mL Pal and Deb (2014)
55. Fe3O4 (iron source–FeSO4⋅7H2O) 68.50 Langmuir Pseudo-2nd-order – 7.0 150.0 40 min 0.015 g/50 mL Wang et al. (2012a)
56. Silver nanoparticles loaded on 66.70 Langmuir Pseudo-2nd-order Endothermic 4.0–7.0 25.0 14.0 min 0.02 g/L Ghaedi et al.
activated carbon (AgNPs-AC) (2012a)
57. Hierarchical urchin-like α-Fe2O3
nanostructures 66.00 Langmuir – – 7.6 100.0 – 1.0 g Fei et al. (2011)
58. AgNPs-coated AC 64.80 Freundlich Pseudo-1st-order – 6.5 ± 0.8 2.0 270 min 7.0 g/100 mL Pal and Deb
(2014)
59. Magnetic iron oxide 54.46 Langmuir Pseudo-2nd-order Optimum temp. 6.0 50.0 300 min 2.0 g/L Paşka et al.
nanopowder (MnP) (45 °C) (2014)
60. Mesoporous α-Fe2O3 53.00 – – – – – – – Yu et al. (2008)
61. Fe(OH)3 49.130 – – – – 100.0 30 min 50 mg/50 mL Wang et al. (2012b)
62. Magnetic core-manganese 42.00 – – – – 80.0 60 min 90 mg/50 mL Zhai et al. (2009)
oxide shell nanoparticles
63. Magnetic nanoparticles 41.99 Langmuir Pseudo-2nd-order Endothermic – – – – Liu et al. (2015b)
Mn-ferrites
64. Reagent NiO nanoparticles 39.70 Langmuir Pseudo-2nd-order – 7.0 25.0 300 min 200.0 mg/L Cheng et al. (2011)
65. Single-crystalline NiO 36.10 – – – – – – – Yang et al. (2007)
nanosheets
66. NiO (111) 35.15 Langmuir Pseudo-2nd-order Endothermic 7.15 50–250 6.0 h 1.25 g/L Song et al. (2009)
67. Hollow Zn–Fe2O4 nanospheres 16.10 Langmuir – – 6.0 5.0 2.0 h 0.02 g/20 mL Rahimi et al. (2011)
68. Nickel oxide nanoparticles 10.10 Langmuir Pseudo-2nd-order – 5.0 2.0 25 min 0.5 g/L Falaki and Fakhri
(2014)
Environ Sci Pollut Res
cellulose/montmorillonite nanocomposite (Zhao and Wang 2012), modified xanthan gum/silica hybrid nanocomposite (Ghorai et al. 2013) and lignocellulose/montmorillonite nano- composite ( 赵 亚 红 et al. 2012), were also prepared,
characterized and successfully applied as adsorbent for the re-
moval of CR.
Kumar et al. (2014) prepared a novel starch/AlOOH/FeS2 nanocomposite, characterized it by SEM, TEM, XPS, FT-IR and N2 adsorption-desorption isotherm and used for the ad- sorption of CR dye from an aqueous solution. The adsorption of CR onto starch/AlOOH/FeS2 was evaluated as a function of contact time, solution pH, concentration and temperature. The adsorption capacity was found to be 333.33 mg/g. A positive value of enthalpy change indicates that the adsorption was endothermic and physical in nature. Adsorption results dem- onstrate that the maximum removal of CR was found to be at pH 5.0. The adsorption kinetics data fitted well to the pseudo- first-order equation, whereas the Freundlich equation exhibits the better correlation to the experimental data.
Yao et a l . ( 2012 ) described the synthesis of magneticFe3O4@graphene composite (FGC) and its use in dye removal of methylene blue (MB) and CR from aqueous media. The structure, surface and magnetic characteristics were investigated by SEM, TEM, EDX-ray spectrometer, XRD, FT-IR and TGA. Through a chemical deposition meth- od, Fe3O4 nanoparticles in a size of 30 mm were homoge- neously dispersed onto graphene sheets. The maximum ad- sorption capacities of MB and CR on FGC were found to be
45.27 and 33.66 mg/g, respectively.
Table 11 presents the maximum adsorption capacities of various composite and nanocomposite materials used for CR.
Miscellaneous adsorbents
Various other materials have also been explored as adsorbents for the removal of CR such as calix[4]arene (II) and amberlite XAD-4TM resin (1) (Kamboh et al. 2009), metal-organic framework (MOF-5) (Khanjani and Morsali 2014), novel acti- vated boron nitride (BN) (Li et al. 2013a), organic-inorganic hybrid mesoporous polymers (Chen et al. 2012), loosely and tightly bound extracellular polymeric substances (LB/TB-EPS) (Gao et al. 2011), interpenetrating polymer network (IPN) type hydrogels (Maity and Ray 2014), porous poly(vinyl alcohol) (PVA) gels (Sandeman et al. 2011), functional polyelectrolyte multilayer membranes (Tripathi et al. 2013) and porous TiO2 (Liu et al. 2014b). The adsorption capacities of various miscel- laneous adsorbent materials are given in Table 12.
Future perspectives
As there are dual advantages (i.e. water treatment and waste management) of wastewater treatment by adsorption process,
Table 11 Maximum adsorption capacities of composites and nanocomposites for CR
Sr. Adsorbents Adsorption Isotherm Kinetic study Thermodynamic pH Initial dye Equilibrium Dosage of References
no. capacity, study study concentration time adsorbent
qmax (mg/g) (mg/L)
1. Lamellar-structured Co/Co(OH)2 2058.00 – – – 7.0 150.0 10 min 4.0 mg/50 mL Wu et al. (2014a)
nanocomposite
2. Polyaniline lignocellulose 1672.50 R-P Pseudo-2nd-order Endothermic 4.29 28.5 30 min 0.69 g Debnath et al. (2015) composite (PLC)
3. α-Fe/Fe3O4 nanocomposite 1297.06 – – – – 100.0 3.0 min 0.1 g/L Wang et al. (2013c)
4. Cobalt hybrid/graphene 934.9 – – – 7.0 100.0 240 min 5.0 mg/50 mL Wang et al. (2013b)
nanocomposite (Co/G
nanocomposite)
5.Hydroxyapatite/chitosan composite
6.TiO2/PA composite (titanium dioxide/palygorskite)
769.00 Langmuir Pseudo-2nd-order Endothermic Natural 400.0 480 min 50 mg/25 mL Hou et al. (2012)
518.13 Langmuir Pseudo-2nd-order Endothermic 7.0 200–2000 90 min 0.2 g/100 mL Peng et al. (2013)
(MWCNTs) decorated with Fe3O4 nanoparticles (MWCNTs/Fe3O4) modified by polyaniline (PANI) [MWCNTs/Fe3O4/PANI
composite]
18. Guar gum-graft-ply
(acrylamide)/silica (g-GG/SiO2) hybrid nanocomposite
(2014)
233.24 Langmuir Pseudo-2nd-order Endothermic 3.0 150.0 30 min 40 mg/25 mL Pal et al. (2015)
19. GO/CS fibers 227.27 Langmuir – – 5.0 20–200 600 min 0.9 g/L Du et al. (2014)
Table 11 (continued)
(HAP/Fe3O4/Zeo) composite
nanocomposite
composite (FGC)
Environ Sci Pollut Res
it is a constant need to identify and develop easily available, economically viable and highly effective adsorbent for effi- cient and facile removal of pollutants (dyes).
In this context, the nanoparticles, composites and nanocomposite adsorbents have demonstrated outstand- ing adsorption capabilities for CR. However, the sepa- ration and aggregation of nanomaterials is also a hurdle to their use in the actual system. Also, the release of the nano-adsorbent in aqueous solution causes toxicity on the living system. Thus, there is a bigger opportunity of research regarding the various measures of mitigating their toxicity to the environment.
In addition, although large numbers of the research articles are continuously being published on the adsorption of CR, few facts must be considered for future research such as the following:
(i)Carry out more work on dye adsorption from mixed pollution effluents under a wide range of operating conditions—Various papers reviewed herein describe adsorption of CR by batch mode. There are only few researches describing water treatment at pilot and industrial scales.
(ii)Perform pilot plant/real industrial effluent adsorption studies—The effectiveness of treatment depends not on- ly on the properties of the adsorbent and adsorbate but also on the environmental conditions and variables used for the adsorption process such as pH, ionic strength, temperature, existence of competing organic or inorgan- ic ligands in solution, contact time and adsorbent con- centration. Regardless of the fact that actual colour bear- ing effluents contains mixed dye pollutants including the presence of salts and other toxic metal ions, less attention has been given. Therefore, much work is necessary to predict the performance of dye adsorption from real in- dustrial effluents.
(iii)Properly investigate the dye adsorption mechanism on various adsorbents because it has been less studied and poorly understood—It has been stated that in the phys- ical adsorption, pollutants get accumulated on adsorbent surfaces by one or more of the interactions, i.e. Van der Waals forces, hydrophobicity, hydrogen bonds, polarity and steric interaction, dipole-induced dipole interaction, π-π interaction, etc. The chemisorption process in- volves the sharing of electrons between the pollutants and the surface of the adsorbent resulting into a chemi- cal bond.
(iv)Do more work on handling of the adsorbent spe- cially nano-sorbents and regeneration of spent ad- sorbent—The management of the exhausted adsor- bent is an important issue and has not been taken care of completely. Thus, more work is necessary in this direction.
Table 12 Maximum adsorption capacities of miscellaneous adsorbents for CR
Sr.
no.
Adsorbents Adsorption capacity, qmax (mg/g)
Isotherm study
Kinetic study Thermodynamic study
pH Initial dye concentration (mg/L)
Equilibrium time
Dosage of adsorbent
References
1.Hyper cross-linked
poly(styrene-co- divinylbenzene) resin (TEPA)
2.Perfluorous conjugated microporous polymer (PFCMP-0)
2326.00 Freundlich Pseudo-2nd-order – – – – – Li et al. (2013b)
1376.70 Langmuir – – – 100.0 3.0 h – Yang et al.
(2015)
3.3D BN architecture 717.50 Langmuir – – – – – – Liu et al.
(2014a)
4.α-MnO2 micronests 625.00 Langmuir Pseudo-2nd-order Endothermic 7.5 200.0 240 min 400 mg/L Zhang et al.
(2014a)
5.Magnetic
chitosan/poly(vinyl alcohol) hydrogel beads
(m-CS/PVA HBs)
6.Hierarchical porous γ-Al2O3
hollow microspheres
7.Organo vermiculite
(200 HDTMA)
470.10 Langmuir Pseudo-2nd-order Endothermic 6.0 – 36 h 0.7 g/50 mL Zhu et al.
(2012a)
322.00 – – – – – – – Li et al. (2014c)
192.31 Langmuir Pseudo-2nd-order Endothermic – – – 25 mg/25 mL Yu et al. (2010)
8.Ce-Fe/RGO-3 179.50 Langmuir Pseudo-2nd-order – – – – – Ling et al.
(2013)
9.Interpenetrating network hydrogel from poly(acrylic acid-co-hydroxyethyl methacrylate) and sodium alginate
10.Graphene oxide (GO)
11.Mesoporous γ-Al2O3
powders
12.Phosphomolybdic acid (PMA)
13.Fe3O4 particles
14.Fe particles
15.Supramolecular sorbent (SiO2-CD)
172.00 Langmuir
and Fritz-
Schlünder models
Pseudo-2nd-order Exothermic – 10–140 – – Mandal and Ray
(2013)
Zhang et al. (2013)
Ghosh and Naskar (2013)
Jeyabalan and Peter (2014)
Wang et al. (2013a)
Wang et al. (2013a)
Chen et al. (2013a)
Table 12 (continued)
Sr.
no. Adsorbents Adsorption capacity, qmax Isotherm study Kinetic study Thermodynamic study pH Initial dye concentration Equilibrium time Dosage of adsorbent References
(mg/g) (mg/L)
16. Nano zero-valent iron/barium 68.30 Langmuir – – 7.0 – 120 min – Yang et al.
ferrite (NZVI/BFO) (2014b)
microfibers
17. ZrO2 hollow spheres 59.5 ± 3 Langmuir Pseudo-2nd-order – 7.0 35.0 500 min 400 mg/L Wang et al.
(2014a)
18. Manganese oxide 58.13 Langmuir Pseudo-2nd-order Endothermic 7.5 500.0 – – Chakrabarti
et al. (2009)
19. Silica gel-chloro 50.11 Langmuir Pseudo-2nd-order 4.0–5.0 200.0 90 min – Shasha et al.
phytahydrodyctionafricanum (2015)
20. Vaterite calcium carbonate 32.60 Langmuir Pseudo-2nd-order Endothermic 5.0 100.0 – 0.2 g Chong et al.
(CaCO3) (2014)
21. Magnetic MnFe2O4 CR = 25.780
CR + MB = 32.203 Langmuir Pseudo-2nd-order – 3.0–9.0 400.0 30 min – Yang et al. (2014a)
22. Hybrid aniline propyl silica 22.62 Sips and R-P Pseudo-2nd-order – 5.0 – 20 min – Pavan et al.
xerogel (SiAn) (2008)
23. ZrO2 solid spheres 21.4 ± 1.1 Langmuir Pseudo-2nd-order – 7.0 35.0 500 min 400 mg/L Wang et al. (2014a)
24. Polypyrrole 18.00 Freundlich Pseudo-1st-order Endothermic 3.0 40.0 40 min 100 mg/50 mL Karthikeyan
et al. (2014)
25. Luffa cylindrica fiber-graft 17.39 Langmuir – Endothermic – – – – Gupta et al.
copolymerization of methyl (2014)
acrylate/acrylamide [Lc-g-
poly (MA/AAm)]
26. 4-Vinyl pyridine-grafted
poly(ethylene terephthalate) 17.30 Langmuir Pseudo-2nd-order – 4.0 300.0 150 min – Arslan and
Yiğitoğlu
fibers (2008)
based silica resin
30.Non-magnetic amine
group-modified (AMS) sugarcane bagasse
31.Magnetic carboxyl
group-modified (MMS) sugarcane bagasse
1.55 mmol/g Langmuir Pseudo-2nd-order – 7.0∼7.5 10 × 10−5
mol/L
0.04 mmol/g Langmuir Pseudo-2nd-order – 7.0∼7.5 10 × 10−5
mol/L
Diouri et al. (2015)
Wang et al. (2014a)
Kamboh
et al. (2012)
400 min 0.05 g/50 mL Yu et al. (2015)
400 min 0.05 g/50 mL Yu et al. (2015)
Table 12 (continued)
Sr.
no. Adsorbents Adsorption capacity, qmax Isotherm study Kinetic study Thermodynamic study pH Initial dye concentration Equilibrium time Dosage of adsorbent References
(mg/g) (mg/L)
32. γ-Al2O3 – – – – – – – – Ghosh et al. (2015)
33. Natural coagulants 98.00 % – – Maximum 4.0 – 60 min 25.0 mg/L Patel and Vashi
Surjana seed powder (SSP) removal at (2012)
340 K
34. Maize seed powder (MSP) 94.50 % – – Maximum 4.0 – 60 min 25.0 mg/L Patel and Vashi
removal at (2012)
340 K
35. Chitosan 89.40 % – – Maximum 4.0 – 60 min 25.0 mg/L Patel and Vashi
removal at (2012)
340 K
36. Graphite oxide – – – – – – – – Barkauskas et
al.
(2011)
37. Poly(N-acryloylmorpholineco- – Langmuir – – – – – – Deen et al.
N-isopropyl acrylamide) (2015)
hydrogels cross-linked with
poly (ethylene glycol)
diacrylate
38. Manganese oxides – – – – – 100.0 30 min – Ge et al.
(2015b)
39. Cu2O submicro-octahedra – – – – – 10.0 80 min 0.10 g/200 mL Zhang et al. (2014b)
40. Nano zero-valent iron – – – – 6.0 40.0 30 min 2.0 g/L Prabu et al.
(NZVI)-impregnated cashew (2015)
nut shell (NZVI-CNS)
41. Polyacrylonitrile (PAN) – – Pseudo-2nd-order – 7.0 42.0 >80 min 0.02 g/50 mL Chen et al.
nanofiber membranes (2013b)
functionalized with
calix[8]arenes (C[8])
[Cal[8]-15/PAN]
Chen et al.
(2013b)
Chen et al. (2013b)
Kamboh et al. (2009)
Kamboh et al.
(1) (2009)
Table 12 (continued)
Sr.
no. Adsorbents Adsorption capacity, qmax Isotherm study Kinetic study Thermodynamic study pH Initial dye concentration Equilibrium time Dosage of adsorbent References
(mg/g) (mg/L)
46. Metal-organic framework – – – – – 50 75 min – Khanjani and
(MOF-5) on silk fiber Morsali
(2014)
47. Novel activated boron – – – – – – – – Li et al. (2013a)
nitride (BN)
48. Organic-inorganic hybrid – – – – 50.0 24.0 h 10 mg/10 mL Chen et al.
mesoporous polymers (2012)
49. Loosely bound extracellular – – – – 6.2 – – – Gao et al.
polymeric substances (2011)
(LB-EPS), tightly bound
EPS (TB-EPS)
50. Interpenetrating polymer – – – – 9.0 200.0 900 min – Maity and Ray
network (IPN) type (2014)
hydrogels
51. Porous poly(vinyl alcohol) – – – – – – – – Sandeman et al.
(PVA) gels (2011)
52. Functional polyelectrolyte – – – – – – – – Tripathi et al.
multilayer membranes (2013)
53. Porous TiO2 – – – – – – – – Liu et al. (2014b)
Conclusions
The pollution of water by coloured effluent is one of the most decisive environmental nuisances throughout the world. To adapt to the increasing draconian environmental regulations, a wide range of treatment technologies such as photocatalytic degradation, sonochemical degradation, sonophotocatalytic degradation, electrochemical processes, ozonation, oxidation processes, enzymatic decoloration and biological degradation have been developed for the removal of colour-producing dyes, like CR, from wastewater. It is evident from the litera- ture survey of more than 25 articles, related to the removal of CR using various methods other than adsorption, that photo- catalytic degradation is the most extensively studied for the removal of CR from aqueous media.
The adsorption process has been widely used to remove colour from wastewater. Thus, this review article presents a wide range of adsorbents such as activated carbon, non- conventional low-cost materials, nanomaterials, composites and nanocomposites used for the removal of CR from aqueous environment. From the literature survey of more than 290 articles related to the adsorption of CR, it is perceived that its mechanism and kinetics of adsorption depend on the chem- ical nature of the materials and various physico-chemical ex- perimental conditions such as solution pH, initial adsorbate concentration, adsorbent dosage and temperature of the sys- tem. Since the CR dye is slightly soluble in water with a pH value of 2.0 as well as its exposure to acid causes colour change from red to blue, due to the п-п* transition of the azo group, the effect of pH was most specifically studied in most of the articles.
Literature review also recognizes that in case of low-cost adsorbents, the modification of the adsorbent leads to an in- crease in the removal efficiency. However, especially to un- derstand the mechanism of adsorption, very less work has been carried out. Thus, there is a good scope of research in this direction.
From the reviewed literature, it is observed that recently a large number of research articles have been published in many well-known journals for the adsorption of CR by using nanomaterial, composite and nanocomposite adsorbents. Although these adsorbents have demonstrated outstanding ad- sorption capabilities for CR, still more research is required in their preparation because many of them which required vari- ous grafting reactions as well as addition of hazardous chemicals have led ultimately to the destruction of the envi- ronment. Thus, there is a bigger opportunity of research re- garding the various measures of mitigating their toxicity to the environment.
The equilibrium adsorption isotherm, kinetic and thermo- dynamic data of different adsorbents were also reviewed, and it is concluded that the Langmuir and Freundlich adsorption isotherm models are frequently used to evaluate the adsorption
capacity of various adsorbents, the kinetic data of adsorption of CR usually follows the pseudo-second-order kinetic model and the adsorption process was found to be endothermic and spontaneous in most of the cases.
Acknowledgments The authors gratefully acknowledge the financial assistance provided by the INSPIRE Programme under the Assured Opportunity for Research Careers (AORC) scheme, funded by the Department of Science and Technology (DST) (Sanction Order No.: DST/INSPIRE Fellowship/2013/66). The authors also acknowledge INFLIBNET (Ahmedabad) for e-journals.
References
Abbas A, Murtaza S, Shahid K (2012a) Batch wise removal of Congo Red dye from its aqueous solution: using Raphanus sativus peel as an adsorbent. LAP LAMBERT Academic Publishing, Saarbrücken
Abbas A, Murtaza S, Shahid K et al (2012b) Comparative study of ad- sorptive removal of Congo Red and brilliant green dyes from water using peanut shell. Middle-East J Sci Res 11:828–832
Acemioğlu B (2004) Adsorption of Congo red from aqueous solution onto calcium-rich fly ash. J Colloid Interface Sci 274:371–379. doi:10.1016/j.jcis.2004.03.019
Afkhami A, Moosavi R (2010) Adsorptive removal of Congo red, a carcinogenic textile dye, from aqueous solutions by maghemite nanoparticles. J Hazard Mater 174:398–403. doi:10.1016/j. jhazmat.2009.09.066
Agag T, Takeichi T (2000) Polybenzoxazine–montmorillonite hybrid nanocomposites: synthesis and characterization. Polymer 41:7083– 7090. doi:10.1016/S0032-3861(00)00064-1
Ahmad R, Kumar R (2010) Adsorptive removal of Congo red dye from aqueous solution using bael shell carbon. Appl Surf Sci 257:1628– 1633. doi:10.1016/j.apsusc.2010.08.111
Ahmad R, Mondal PK (2010) Application of modified water nut carbon as a sorbent in Congo red and malachite green dye contaminated wastewater remediation. Sep Sci Technol 45:394–403. doi:10.1080/ 01496390903484875
Ahmad A, Mohd-Setapar SH, Chuong CS et al (2015) Recent advances in new generation dye removal technologies: novel search for ap- proaches to reprocess wastewater. RSC Adv 5:30801–30818. doi: 10.1039/C4RA16959J
Ahmadi K, Ghaedi M, Ansari A (2014) Comparison of nickel doped zinc sulfide and/or palladium nanoparticle loaded on activated carbon as efficient adsorbents for kinetic and equilibrium study of removal of Congo Red dye. Spectrochim Acta A Mol Biomol Spectrosc 136PC:1441–1449. doi:10.1016/j.saa.2014.10.034
Ahmedi A, Abouseoud M, Abdeltif A, Annabelle C (2015) Effect of diffusion on discoloration of Congo red by alginate entrapped turnip (Brassica rapa) peroxidase. Enzyme Res. doi:10.1155/2015/575618
Ai L, Zeng Y (2013) Hierarchical porous NiO architectures as highly recyclable adsorbents for effective removal of organic dye from aqueous solution. Chem Eng J 215–216:269–278. doi:10.1016/j. cej.2012.10.059
Ai L, Yue H, Jiang J (2012) Sacrificial template-directed synthesis of mesoporous magnesium oxide architectures with superior perfor- mance for organic dye adsorption [corrected]. Nanoscale 4:5401– 5408. doi:10.1039/c2nr31333b
Ai L, Zeng Y, Jiang J (2014) Hierarchical porous BiOI architectures: facile microwave nonaqueous synthesis, characterization and appli- cation in the removal of Congo red from aqueous solution. Chem Eng J 235:331–339. doi:10.1016/j.cej.2013.09.046
Akgül M (2014) Enhancement of the anionic dye adsorption capacity of clinoptilolite by Fe(3+)-grafting. J Hazard Mater 267:1–8. doi:10. 1016/j.jhazmat.2013.12.040
Akkaya Sayğılı G (2015) Synthesis, characterization and adsorption properties of a novel biomagnetic composite for the removal of Congo red from aqueous medium. J Mol Liq 211:515–526. doi: 10.1016/j.molliq.2015.07.048
Akl M, Youssef A, Al-Awadhi M (2013) Adsorption of acid dyes onto bentonite and surfactant-modified bentonite. J Anal Bioanal Tech 04:1–7. doi:10.4172/2155-9872.1000174
Al-Degs Y, Khraisheh MAM, Allen SJ, Ahmad MN (2000) Effect of carbon surface chemistry on the removal of reactive dyes from tex- tile effluent. Water Res 34:927–935. doi:10.1016/S0043-1354(99) 00200-6
Al-Haidari AA, Al-Taweel SSJ, Jassim LS (2013) Adsorptive removal of Congo red from aqueous solution by local chaff surface: thermody- namics and kinetics studies. Ibn Al-Haitham J Pure Appl Sci 26: 166–177
Ali H (2010) Biodegradation of synthetic dyes—a review. Water Air Soil Pollut 213:251–273. doi:10.1007/s11270-010-0382-4
Ali I (2012) New generation adsorbents for water treatment. Chem Rev 112:5073–5091. doi:10.1021/cr300133d
Alsenani G (2014) Removal of Congo red dye from aqueous solution by date palm leaf base. Am J Appl Sci 11:1553–1557. doi:10.3844/ ajassp.2014.1553.1557
Amran MB, Zulfikar MA (2010) Removal of Congo Red dye by adsorp- tion onto phyrophyllite. Int J Environ Stud 67:911–921. doi:10. 1080/00207233.2010.528256
Anastopoulos I, Kyzas GZ (2014) Agricultural peels for dye adsorption: a review of recent literature. J Mol Liq 200(Part B):381–389. doi:10. 1016/j.molliq.2014.11.006
Anjaneyulu Y, Chary NS, Raj DSS (2005) Decolourization of industrial effluents—available methods and emerging technologies—a re- view. Rev Environ Sci Biotechnol 4:245–273. doi:10.1007/ s11157-005-1246-z
Annadurai G, Juang R-S, Lee D-J (2002) Use of cellulose-based wastes for adsorption of dyes from aqueous solutions. J Hazard Mater 92: 263–274. doi:10.1016/S0304-3894(02)00017-1
Arslan M, Yiğitoğlu M (2008) Adsorption behavior of Congo red from an aqueous solution on 4-vinyl pyridine grafted poly(ethylene tere- phthalate) fibers. J Appl Polym Sci 107:2846–2853. doi:10.1002/ app.27389
Attallah MF, Ahmed IM, Hamed MM (2013) Treatment of industrial wastewater containing Congo Red and Naphthol Green B using low-cost adsorbent. Environ Sci Pollut Res 20:1106–1116. doi:10. 1007/s11356-012-0947-4
Babel S, Kurniawan TA (2003) Low-cost adsorbents for heavy metals uptake from contaminated water: a review. J Hazard Mater 97:219– 243. doi:10.1016/S0304-3894(02)00263-7
Bagheri M, Mahjoub AR, Mehri B (2014) Enhanced photocatalytic deg- radation of Congo red by solvothermally synthesized CuInSe2–ZnO nanocomposites. RSC Adv 4:21757–21764. doi:10.1039/ C4RA01753F
Baitod J, Upadhyay K, Srivastava JK (2015) Removal of Congo red and methylene blue by using low cost adsorbent. J Ind Pollut Control 31: 17–24
Banat IM, Nigam P, Singh D, Marchant R (1996) Microbial decoloriza- tion of textile-dye-containing effluents: a review. Bioresour Technol 58:217–227. doi:10.1016/S0960-8524(96)00113-7
Banerjee S, Dastidar MG (2005) Use of jute processing wastes for treat- ment of wastewater contaminated with dye and other organics. Bioresour Technol 96:1919–1928. doi:10.1016/j.biortech.2005.01. 039
Bansal RC, Goyal M (2005) Activated carbon adsorption. CRC, Boca Raton
Barkauskas J, Stankevičienė I, Dakševič J, Padarauskas A (2011) Interaction between graphite oxide and Congo red in aqueous me- dia. Carbon 49:5373–5381. doi:10.1016/j.carbon.2011.08.004
Basava Rao VV, Ram Mohan Rao S (2006) Adsorption studies on treat- ment of textile dyeing industrial effluent by flyash. Chem Eng J 116: 77–84. doi:10.1016/j.cej.2005.09.029
Bayat B (2002) Comparative study of adsorption properties of Turkish fly ashes: I. The case of nickel(II), copper(II) and zinc(II). J Hazard Mater 95:251–273. doi:10.1016/S0304-3894(02)00140-1
Bejarano-Pérez NJ, Suárez-Herrera MF (2007) Sonophotocatalytic deg- radation of Congo red and methyl orange in the presence of TiO2 as a catalyst. Ultrason Sonochem 14:589–595. doi:10.1016/j.ultsonch. 2006.09.011
Belhachemi M, Addoun F (2012) Adsorption of Congo red onto activated carbons having different surface properties: studies of kinetics and adsorption equilibrium. Desalination Water Treat 37:122–129. doi: 10.1080/19443994.2012.661263
Bello OS, Bello IA, Adegoke KA (2013) Adsorption of dyes using dif- ferent types of sand: a review. South Afr J Chem 66:117–129 Bhatnagar A, Jain AK, Mukul MK (2005) Removal of Congo red dye
from water using carbon slurry waste. Environ Chem Lett 2:199– 202. doi:10.1007/s10311-004-0097-0
Bhattacharyya KG, Sharma A (2004) Azadirachta indica leaf powder as an effective biosorbent for dyes: a case study with aqueous Congo Red solutions. J Environ Manage 71:217–229. doi:10.1016/j. jenvman.2004.03.002
Bhattacharyya KG, Gupta SS, Sarma GK (2015) Kinetics, equilibrium isotherms and thermodynamics of adsorption of Congo red onto natural and acid-treated kaolinite and montmorillonite. Desalination Water Treat 53:530–542. doi:10.1080/19443994. 2013.839405
Bhaumik M, McCrindle R, Maity A (2013) Efficient removal of Congo red from aqueous solutions by adsorption onto interconnected poly- pyrrole–polyaniline nanofibres. Chem Eng J 228:506–515. doi:10. 1016/j.cej.2013.05.026
Bhaumik M, Choi HJ, McCrindle RI, Maity A (2014) Composite nano- fibers prepared from metallic iron nanoparticles and polyaniline: high performance for water treatment applications. J Colloid Interface Sci 425:75–82. doi:10.1016/j.jcis.2014.03.031
Bhaumik M, McCrindle RI, Maity A (2015) Enhanced adsorptive degra- dation of Congo red in aqueous solutions using polyaniline/Fe0 composite nanofibers. Chem Eng J 260:716–729. doi:10.1016/j. cej.2014.09.014
Bhushan B (ed) (2010) Springer handbook of nanotechnology. Springer, Berlin
Binupriya AR, Sathishkumar M, Swaminathan K et al (2008) Comparative studies on removal of Congo red by native and mod- ified mycelial pellets of Trametes versicolor in various reactor modes. Bioresour Technol 99:1080–1088. doi:10.1016/j.biortech. 2007.02.022
Bulut E, Özacar M, Şengil İA (2008) Equilibrium and kinetic data and process design for adsorption of Congo Red onto bentonite. J Hazard Mater 154:613–622. doi:10.1016/j.jhazmat.2007.10.071
Buzea C, Pacheco II, Robbie K (2007) Nanomaterials and nanoparticles: sources and toxicity. Biointerphases 2:MR17–MR71. doi:10.1116/ 1.2815690
Cai W, Yu J, Cheng B et al (2009) Synthesis of boehmite hollow core/shell and hollow microspheres via sodium tartrate-mediated phase transformation and their enhanced adsorption performance in water treatment. J Phys Chem C 113:14739–14746. doi:10. 1021/jp904570z
Cai W, Yu J, Jaroniec M (2010) Template-free synthesis of hierarchical spindle-like γ-Al2O3 materials and their adsorption affinity towards organic and inorganic pollutants in water. J Mater Chem 20:4587– 4594. doi:10.1039/B924366F
Chakrabarti S, Dutta BK, Apak R (2009) Active manganese oxide: a novel adsorbent for treatment of wastewater containing azo dye. Water Sci Technol J Int Assoc Water Pollut Res 60:3017–3024. doi:10.2166/wst.2009.758
Chakraborty S, Basak B, Dutta S et al (2013) Decolorization and biodeg- radation of Congo red dye by a novel white rot fungus Alternaria alternata CMERI F6. Bioresour Technol 147:662–666. doi:10.1016/ j.biortech.2013.08.117
Chander M, Singh D, Kaur R (2014) Biodecolourisation of reactive red an industrial dye by Phlebia spp. J Environ Biol Acad Environ Biol India 35:1031–1036
Chatterjee S, Chatterjee S, Chatterjee BP, Guha AK (2007) Adsorptive removal of Congo red, a carcinogenic textile dye by chitosan hydrobeads: binding mechanism, equilibrium and kinetics. Colloids Surf Physicochem Eng Asp 299:146–152. doi:10.1016/j. colsurfa.2006.11.036
Chatterjee S, Lee DS, Lee MW, Woo SH (2009a) Enhanced adsorption of Congo red from aqueous solutions by chitosan hydrogel beads im- pregnated with cetyl trimethyl ammonium bromide. Bioresour Technol 100:2803–2809. doi:10.1016/j.biortech.2008.12.035
Chatterjee S, Lee DS, Lee MW, Woo SH (2009b) Congo red adsorption from aqueous solutions by using chitosan hydrogel beads impreg- nated with nonionic or anionic surfactant. Bioresour Technol 100: 3862–3868. doi:10.1016/j.biortech.2009.03.023
Chatterjee S, Lee MW, Woo SH (2009c) Influence of impregnation of chitosan beads with cetyl trimethyl ammonium bromide on their structure and adsorption of Congo red from aqueous solutions. Chem Eng J 155:254–259. doi:10.1016/j.cej.2009.07.051
Chatterjee S, Chatterjee T, Woo SH (2010a) A new type of chitosan hydrogel sorbent generated by anionic surfactant gelation. Bioresour Technol 101:3853–3858. doi:10.1016/j.biortech.2009. 12.089
Chatterjee S, Lee MW, Woo SH (2010b) Adsorption of Congo red by chitosan hydrogel beads impregnated with carbon nanotubes. Bioresour Technol 101:1800–1806. doi:10.1016/j.biortech.2009. 10.051
Chatterjee S, Chatterjee T, Lim S-R, Woo SH (2011a) Effect of the addi- tion mode of carbon nanotubes for the production of chitosan hy- drogel core-shell beads on adsorption of Congo red from aqueous solution. Bioresour Technol 102:4402–4409. doi:10.1016/j. biortech.2010.12.117
Chatterjee S, Chatterjee T, Lim S-R, Woo SH (2011b) Effect of surfactant impregnation into chitosan hydrogel beads formed by sodium dode- cyl sulfate gelation for the removal of Congo red. Sep Sci Technol 46:2022–2031. doi:10.1080/01496395.2011.592520
Chaudhary GR, Saharan P, Kumar A et al (2013) Adsorption studies of cationic, anionic and azo-dyes via monodispersed Fe3O4 nanopar- ticles. J Nanosci Nanotechnol 13:3240–3245
Chen H, Zhao J (2009) Adsorption study for removal of Congo red anionic dye using organo-attapulgite. Adsorption 15:381–389. doi: 10.1007/s10450-009-9155-z
Chen T, Du B, Fan Z (2012) Organic–inorganic hybrid mesoporous poly- mers fabricated by using (CTA)2S2O8 as self-decomposed soft tem- plates. Langmuir ACS J Surf Colloids 28:15024–15032. doi:10. 1021/la302346g
Chen M, Ding W, Wang J, Diao G (2013a) Removal of azo dyes from water by combined techniques of adsorption, desorption, and elec- trolysis based on a supramolecular sorbent. Ind Eng Chem Res 52: 2403–2411. doi:10.1021/ie300916d
Chen M, Wang C, Fang W et al (2013b) Electrospinning of calixarene- functionalized polyacrylonitrile nanofiber membranes and applica- tion as an adsorbent and catalyst support. Langmuir ACS J Surf Colloids 29:11858–11867. doi:10.1021/la4017799
Chen Z-Y, Gao H-W, He Y-Y (2013c) Selective photodegradation and backfilling for regeneration of the inorganic–organic hybrid com- posite Fe3O4@C18ADB@Zn2SiO4 which captures organic
pollutants from aqueous solution. RSC Adv 3:5815–5818. doi:10. 1039/C3RA22324H
Chen R, Wang W, Zhao X et al (2014) Rapid hydrothermal synthesis of magnetic CoxNi1−xFe2O4 nanoparticles and their application on removal of Congo red. Chem Eng J 242:226–233. doi:10.1016/j.
cej.2013.12.016
Chen X, Zhang F, Wang Q et al (2015) The synthesis of ZnO/SnO2 porous nanofibers for dye adsorption and degradation. Dalton Trans Camb Engl 2003 44:3034–3042. doi:10.1039/c4dt03382e
Cheng B, Le Y, Cai W, Yu J (2011) Synthesis of hierarchical Ni(OH)2 and NiO nanosheets and their adsorption kinetics and isotherms to Congo red in water. J Hazard Mater 185:889–897. doi:10.1016/j. jhazmat.2010.09.104
Cheng Z, Zhang L, Guo X et al (2015) Adsorption behavior of direct red 80 and Congo red onto activated carbon/surfactant: process optimi- zation, kinetics and equilibrium. Spectrochim Acta A Mol Biomol Spectrosc 137:1126–1143. doi:10.1016/j.saa.2014.08.138
Chong KY, Chia CH, Zakaria S, Sajab MS (2014) Vaterite calcium car- bonate for the adsorption of Congo red from aqueous solutions. J Environ Chem Eng 2:2156–2161. doi:10.1016/j.jece.2014.09.017
Chou K-S, Tsai J-C, Lo C-T (2001) The adsorption of Congo red and vacuum pump oil by rice hull ash. Bioresour Technol 78:217–219. doi:10.1016/S0960-8524(00)00116-4
Chowdhury AK, Sarkar AD, Bandyopadhyay A (2009) Rice husk ash as a low cost adsorbent for the removal of methylene blue and Congo red in aqueous phases. CLEAN – Soil Air Water 37:581–591. doi: 10.1002/clen.200900051
Cotoruelo LM, Marqués MD, Díaz FJ et al (2010) Equilibrium and ki- netic study of Congo red adsorption onto lignin-based activated carbons. Transp Porous Media 83:573–590. doi:10.1007/s11242- 009-9460-8
Crini G (2006) Non-conventional low-cost adsorbents for dye removal: a review. Bioresour Technol 97:1061–1085. doi:10.1016/j.biortech. 2005.05.001
Dawood S, Sen TK (2012) Removal of anionic dye Congo red from aqueous solution by raw pine and acid-treated pine cone powder as adsorbent: equilibrium, thermodynamic, kinetics, mechanism and process design. Water Res 46:1933–1946. doi:10.1016/j. watres.2012.01.009
Dawood S, Sen T (2014) Review on dye removal from its aqueous solu- tion into alternative cost effective and non-conventional adsorbents. J Chem Proc Engg 1:1–7
Debnath S, Kitinya J, Onyango MS (2014) Removal of Congo red from aqueous solution by two variants of calcium and iron based mixed oxide nano-particle agglomerates. J Ind Eng Chem 20:2119–2129. doi:10.1016/j.jiec.2013.09.041
Debnath S, Ballav N, Maity A, Pillay K (2015) Development of a polyaniline-lignocellulose composite for optimal adsorption of Congo red. Int J Biol Macromol 75:199–209. doi:10.1016/j. ijbiomac.2015.01.011
Deen GR, Lim ZL, Mah CH et al (2015) Network structure and Congo red dye removal characteristics of new temperature-responsive hydrogels. Sep Sci Technol 50:64–71. doi:10.1080/01496395. 2014.949349
Dehghanian N, Ghaedi M, Ansari A et al (2015) A random forest ap- proach for predicting the removal of Congo red from aqueous solu- tions by adsorption onto tin sulfide nanoparticles loaded on activated carbon. Desalination Water Treat 0:1–14. doi:10.1080/19443994. 2015.1027964
Demirbas A (2009) Agricultural based activated carbons for the removal of dyes from aqueous solutions: a review. J Hazard Mater 167:1–9. doi:10.1016/j.jhazmat.2008.12.114
Deo N, Ali M (1993) Dye adsorption by a new low-cost material: Congo red—1. Indian J Environ Prot 13:496–508
Devi LG, Murthy BN, Kumar SG (2010) Photocatalytic activity of TiO2 doped with Zn2+ and V5+ transition metal ions: influence of
crystallite size and dopant electronic configuration on photocatalytic activity. Mater Sci Eng B 166:1–6. doi:10.1016/j.mseb.2009.09.008 Dhal JP, Mishra BG, Hota G (2014) Ferrous oxalate, maghemite and hematite nanorods as efficient adsorbents for decontamination of Congo red dye from aqueous system. Int J Environ Sci Technol 1–
12. doi:10.1007/s13762-014-0535-x
Diouri K, Kherbeche A, Chaqroune A (2015) Kinetics of Congo red dye adsorption onto marble powder sorbents. Int J Innov Res Sci Eng Technol 4:267–274. doi:10.15680/IJIRSET.2015.0402056
Du Q, Sun J, Li Y et al (2014) Highly enhanced adsorption of Congo red onto graphene oxide/chitosan fibers by wet-chemical etching off silica nanoparticles. Chem Eng J 245:99–106. doi:10.1016/j.cej. 2014.02.006
Erdemoğlu S, Aksu SK, Sayilkan F et al (2008) Photocatalytic degrada- tion of Congo Red by hydrothermally synthesized nanocrystalline TiO2 and identification of degradation products by LC-MS. J Hazard Mater 155:469–476. doi:10.1016/j.jhazmat.2007.11.087
Falaki F, Fakhri A (2014) Adsorption properties of nickel oxide nanopar- ticles for removal of Congo Red from aqueous solution. J Phys Theor Chem Islam Azad Univ Iran 10:255–262
Fang Q, Lin J-W, Zhan Y-H et al (2014) Synthesis of hydroxyapatite/ magnetite/zeolite composite for Congo red removal from aqueous solution. Huan Jing Ke Xue Huanjing Kexue Bian Ji Zhongguo Ke Xue Yuan Huan Jing Ke Xue Wei Yuan Hui Huan Jing Ke Xue Bian Ji Wei Yuan Hui 35:2992–3001
Faouzi Elahmadi M, Bensalah N, Gadri A (2009) Treatment of aqueous wastes contaminated with Congo Red dye by electrochemical oxi- dation and ozonation processes. J Hazard Mater 168:1163–1169. doi:10.1016/j.jhazmat.2009.02.139
Fei JB, Cui Y, Yan XH et al (2008) Controlled preparation of MnO2 hierarchical hollow nanostructures and their application in water treatment. Adv Mater 20:452–456. doi:10.1002/adma.200701231
Fei J, Cui Y, Zhao J et al (2011) Large-scale preparation of 3D self- assembled iron hydroxide and oxide hierarchical nanostructures and their applications for water treatment. J Mater Chem 21: 11742–11746. doi:10.1039/C1JM11950H
Feng T, Zhang F, Wang J, Huang Z (2011) Notice of retraction. Adsorption of Congo red by cross-linked chitosan film. In: (iCBBE) 2011 5th International Conference on Bioinformatics and Biomedical Engineering. pp 1–4
Feng T, Zhang F, Wang J, Wang L (2012) Application of chitosan-coated quartz sand for Congo red adsorption from aqueous solution. J Appl Polym Sci 125:1766–1772. doi:10.1002/app.35670
Forgacs E, Cserháti T, Oros G (2004) Removal of synthetic dyes from wastewaters: a review. Environ Int 30:953–971. doi:10.1016/j. envint.2004.02.001
Foroughi-dahr M, Abolghasemi H, Esmaili M et al (2015a) Adsorption characteristics of Congo red from aqueous solution onto tea waste. Chem Eng Commun 202:181–193. doi:10.1080/00986445.2013. 836633
Foroughi-dahr M, Abolghasemi H, Esmaieli M et al (2015b) Experimental study on the adsorptive behavior of Congo red in cationic surfactant-modified tea waste. Process Saf Environ Prot 95:226–236. doi:10.1016/j.psep.2015.03.005
Foroughi-dahr M, Esmaieli M, Abolghasemi H et al (2015c) Continuous adsorption study of Congo red using tea waste in a fixed-bed col- umn. Desalination Water Treat 0:1–10. doi:10.1080/19443994. 2015.1021849
Fu Y, Viraraghavan T (2001) Fungal decolorization of dye wastewaters: a review. Bioresour Technol 79:251–262. doi:10.1016/S0960- 8524(01)00028-1
Fu Y, Viraraghavan T (2002) Removal of Congo Red from an aqueous solution by fungus Aspergillus niger. Adv Environ Res 7:239–247. doi:10.1016/S1093-0191(01)00123-X
Fu Y-Q, Zhu H, Yin L et al (2015) Preparation and properties of novel magnetic Rhizopus oryzae biomass particles for removal of Congo
red from aqueous solution. Asian J Chem 27:2036–2042. doi:10. 14233/ajchem.2015.17678
Gamage A, Shahidi F (2007) Use of chitosan for the removal of metal ion contaminants and proteins from water. Food Chem 104:989–996. doi:10.1016/j.foodchem.2007.01.004
Gao J-F, Zhang Q, Wang J-H et al (2011) Contributions of functional groups and extracellular polymeric substances on the biosorption of dyes by aerobic granules. Bioresour Technol 102:805–813. doi: 10.1016/j.biortech.2010.08.119
Ge X, Gu CD, Wang XL, Tu JP (2015a) Spinel type CoFe oxide porous nanosheets as magnetic adsorbents with fast removal ability and facile separation. J Colloid Interface Sci 454:134–143. doi:10. 1016/j.jcis.2015.05.013
Ge X, Gu CD, Wang XL, Tu JP (2015b) Endowing manganese oxide with fast adsorption ability through controlling the manganese car- bonate precursor assembled in ionic liquid. J Colloid Interface Sci 438:149–158. doi:10.1016/j.jcis.2014.09.029
Geetha KS, Belagali SL (2015) Adsorption studies of some dyes on Acacia concinna powder. Int J Res Eng Technol 04:216–221. doi: 10.15623/ijret.2015.0402028
Ghaedi M, Ramazani S, Roosta M (2011) Gold nanoparticle loaded acti- vated carbon as novel adsorbent for the removal of Congo red. Indian J Sci Technol 4:1208–1217
Ghaedi M, Biyareh MN, Kokhdan SN et al (2012a) Comparison of the efficiency of palladium and silver nanoparticles loaded on activated carbon and zinc oxide nanorods loaded on activated carbon as new adsorbents for removal of Congo red from aqueous solution: kinetic and isotherm study. Mater Sci Eng C 32:725–734. doi:10.1016/j. msec.2012.01.015
Ghaedi M, Tavallali H, Sharifi M et al (2012b) Preparation of low cost activated carbon from Myrtus communis and pomegranate and their efficient application for removal of Congo red from aqueous solu- tion. Spectrochim Acta A Mol Biomol Spectrosc 86:107–114. doi: 10.1016/j.saa.2011.10.012
Gharbani P, Tabatabaii SM, Mehrizad A (2008) Removal of Congo red from textile wastewater by ozonation. Int J Environ Sci Technol 5: 495–500. doi:10.1007/BF03326046
Ghorai S, Sarkar AK, Panda AB, Pal S (2013) Effective removal of Congo red dye from aqueous solution using modified xanthan gum/silica hybrid nanocomposite as adsorbent. Bioresour Technol 144:485–491. doi:10.1016/j.biortech.2013.06.108
Ghosh D, Bhattacharyya KG (2002) Adsorption of methylene blue on kaolinite. Appl Clay Sci 20:295–300. doi:10.1016/S0169-1317(01) 00081-3
Ghosh S, Naskar MK (2013) Solvothermal conversion of nanofiber to nanorod-like mesoporous γ-Al2O3 powders, and study their ad- sorption efficiency for Congo red. J Am Ceram Soc 96:1698– 1701. doi:10.1111/jace.12368
Ghosh S, Bose P, Basak S, Naskar MK (2015) Solvothermal-assisted evaporation-induced self-assembly process for significant improve- ment in the textural properties of γ-Al2O3, and study dye adsorption efficiency. J Asian Ceram Soc 3:198–205. doi:10.1016/j.jascer. 2015.02.005
Ghribi A, Bagane M, Chlendi M (2014) Sorptive removal of Congo red from aqueous solutions using raw clay: batch and dynamic studies. Int J Innov Environ Stud Res 2:45–56
Gimenez GG, Ruiz SP, Caetano W et al (2014) Biosorption potential of synthetic dyes by heat-inactivated and live Lentinus edodes CCB-42 immobilized in loofa sponges. World J Microbiol Biotechnol 30: 3229–3244. doi:10.1007/s11274-014-1750-9
Giri SK, Das NN, Pradhan GC (2011) Synthesis and characterization of magnetite nanoparticles using waste iron ore tailings for adsorptive removal of dyes from aqueous solution. Colloids Surf Physicochem Eng Asp 389:43–49. doi:10.1016/j.colsurfa.2011.08.052
Golder AK, Samanta AN, Ray S (2006) Anionic reactive dye removal from aqueous solution using a new adsorbent—sludge generated in
removal of heavy metal by electrocoagulation. Chem Eng J 122: 107–115. doi:10.1016/j.cej.2006.06.003
Gomathi Devi L, Narasimha Murthy B, Girish Kumar S (2009) Heterogeneous photo catalytic degradation of anionic and cationic dyes over TiO(2) and TiO(2) doped with Mo(6+) ions under solar light: correlation of dye structure and its adsorptive tendency on the degradation rate. Chemosphere 76:1163–1166. doi:10.1016/j. chemosphere.2009.04.005
Gopinath KP, Muthukumar K, Velan M (2010) Sonochemical deg- radation of Congo red: optimization through response surface methodology. Chem Eng J 157:427–433. doi:10.1016/j.cej. 2009.12.002
Guo H, Ke Y, Wang D et al (2013) Efficient adsorption and photocatalytic degradation of Congo red onto hydrothermally synthesized NiS nanoparticles. J Nanoparticle Res. doi:10.1007/s11051-013-1475-y
Guo H, Chen J, Weng W et al (2014) Adsorption behavior of Congo red from aqueous solution on La2O3-doped TiO2 nanotubes. J Ind Eng Chem 20:3081–3088. doi:10.1016/j.jiec.2013.11.047
Gupta VK, Suhas (2009) Application of low-cost adsorbents for dye removal—a review. J Environ Manage 90:2313–2342. doi:10. 1016/j.jenvman.2008.11.017
Gupta VK, Mittal A, Malviya A, Mittal J (2009) Adsorption of carmoisine A from wastewater using waste materials—bottom ash and deoiled soya. J Colloid Interface Sci 335:24–33. doi:10.1016/j. jcis.2009.03.056
Gupta VK, Kumar R, Nayak A et al (2013a) Adsorptive removal of dyes from aqueous solution onto carbon nanotubes: a review. Adv Colloid Interface Sci 193–194:24–34. doi:10.1016/j.cis.2013.03. 003
Gupta VK, Pathania D, Singh P et al (2013b) Cellulose acetate-zirconium
(IV) phosphate nano-composite with enhanced photo-catalytic ac- tivity. Carbohydr Polym 95:434–440. doi:10.1016/j.carbpol.2013. 02.045
Gupta VK, Pathania D, Agarwal S, Sharma S (2014) Amputation of Congo red dye from waste water using microwave induced grafted Luffa cylindrica cellulosic fiber. Carbohydr Polym 111:556–566. doi:10.1016/j.carbpol.2014.04.032
Hamerlinck Y, Mertens DH, Vansant EF (1994) Activated carbon princi- ples in separation technology. Elsevier, New York
Han R, Ding D, Xu Y et al (2008) Use of rice husk for the adsorption of Congo red from aqueous solution in column mode. Bioresour Technol 99:2938–2946. doi:10.1016/j.biortech.2007.06.027
Han X, Tian P, Pang H et al (2014) Facile synthesis of magnetic hierar- chical MgO–MgFe2O4 composites and their adsorption perfor- mance towards Congo red. RSC Adv 4:28119–28125. doi:10. 1039/C4RA02313G
Hao T, Rao X, Li Z et al (2014a) Synthesis of magnetic separable iron oxide/carbon nanocomposites for efficient adsorptive removal of Congo red. J Alloys Compd 617:76–80. doi:10.1016/j.jallcom. 2014.07.111
Hao T, Yang C, Rao X et al (2014b) Facile additive-free synthesis of iron oxide nanoparticles for efficient adsorptive removal of Congo red and Cr(VI). Appl Surf Sci 292:174–180. doi:10.1016/j.apsusc.2013. 11.108
Hashemian S, Foroghimoqhadam A (2014) Effect of copper doping on CoTiO3 ilmenite type nanoparticles for removal of Congo red from aqueous solution. Chem Eng J 235:299–306. doi:10.1016/j.cej. 2013.08.089
Hernández-Zamora M, Cristiani-Urbina E, Martínez-Jerónimo F et al (2015) Bioremoval of the azo dye Congo Red by the microalga Chlorella vulgaris. Environ Sci Pollut Res Int 22:10811–10823. doi:10.1007/s11356-015-4277-1
Hou H, Zhou R, Wu P, Wu L (2012) Removal of Congo red dye from aqueous solution with hydroxyapatite/chitosan composite. Chem Eng J 211–212:336–342. doi:10.1016/j.cej.2012.09.100
Hu Z, Chen H, Ji F, Yuan S (2010) Removal of Congo Red from aqueous solution by cattail root. J Hazard Mater 173:292–297. doi:10.1016/j. jhazmat.2009.08.082
Hu J, Yu H, Dai W et al (2014) Enhanced adsorptive removal of hazard- ous anionic dye Bcongo red^ by a Ni/Cu mixed-component metal– organic porous material. RSC Adv 4:35124. doi:10.1039/
C4RA05772D
Huang HY, Luo LD, Zhang H et al (2014) Adsorption of Congo red from aqueous solutions by the activated carbons prepared from grapefruit peel. Appl Mech Mater 529:3–7. doi:10.4028/www.scientific.net/ AMM.529.3
Hussain F, Hojjati M, Okamoto M, Gorga RE (2006) Review article: Polymer-matrix nanocomposites, processing, manufacturing, and application: an overview. J Compos Mater 40:1511–1575. doi:10. 1177/0021998306067321
Jain R, Sikarwar S (2014) Adsorption and desorption studies of Congo red using low-cost adsorbent: activated de-oiled mustard. Desalination Water Treat 52:7400–7411. doi:10.1080/19443994. 2013.837004
Janveja B, Sharma J (2011) Removal of Congo red dye from aqueous solutions using steam activated pigmented rice husk carbon as an adsorbent: a thermodynamic study. J Int Acad Phys Sci 15:478–495 Jayaraj R, Jeyasingh Thanaraj P, Thillai Natarajan S, Martin Deva Prasath P (2011) Removal of Congo red dye from aqueous solution using
acid activated eco-friendly low cost carbon prepared from marine algae Valoria bryopsis. J Chem Pharm Res 3:389–396
Jeyabalan T, Peter P (2014) Degradation of dyes (methylene blue and Congo red dye) using phosphomolybdic acid. Int J Sci Res 3: 2312–2315
Jia X, Song H-J, Min C, Zhang X-Q (2012) One-step synthesis of Fe3O4 nanorods/graphene nanocomposites. Appl Phys A 109:261–265. doi:10.1007/s00339-012-7278-7
Jiang R, Yao J, Zhu H et al (2014) Effective decolorization of Congo red in aqueous solution by adsorption and photocatalysis using novel magnetic alginate/γ-Fe2O3/CdS nanocomposite. Desalination Water Treat 52:238–247. doi:10.1080/19443994.2013.787551
Jin L-N, Liu Q, Yang Y et al (2014) Large-scale preparation of indium- based infinite coordination polymer hierarchical nanostructures and their good capability for water treatment. J Colloid Interface Sci 426: 1–8. doi:10.1016/j.jcis.2014.03.066
Jin L-N, Qian X-Y, Wang J-G et al (2015) MIL-68 (In) nano-rods for the removal of Congo red dye from aqueous solution. J Colloid Interface Sci 453:270–275. doi:10.1016/j.jcis.2015.05.005
Jirekara DB, Farooquib M (2015) Adsorption of Congo red dye from aqueous solution using eco-friendly low cost material prepared from Cicerarientinum. Arab J Phys Chem 2:1–6
Kamboh MA, Solangi IB, Sherazi STH, Memon S (2009) Synthesis and application of calix[4]arene based resin for the removal of azo dyes. J Hazard Mater 172:234–239. doi: 10.1016/j.jhazmat.2009.06.165
Kamboh MA, Solangi IB, Sherazi STH, Memon S (2012) Sorption of Congo red onto p-tert-butylcalix[4]arene based silica resin. J Iran Chem Soc 8:272–279. doi:10.1007/BF03246224
Kannan N, Meenakshisundaram M (2002) Adsorption of Congo red on various activated carbons. a comparative study. Water Air Soil Pollut 138:289–305. doi:10.1023/A:1015551413378
Karthikaikumar S, Karthikeyan M, Satheesh Kumar K (2014) Removal of Congo red dye from aqueous solution by polyaniline- montmorrillonite composite. Chem Sci Rev Lett 2:606–614
Karthikeyan M, Raj Kumar P, Prabhakaran A et al (2014) Studies on the removal of dyes using polypyrrole—a kinetic and thermodynamic approach. Int J Res Chem Environ 4:149–155
Kaur H, Thakur A (2014) Adsorption of Congo red dye from aqueous solution onto ash of Cassia fistula seeds: kinetic and thermodynamic studies. Chem Sci Rev Lett 3:159–169
Kaur S, Rani S, Mahajan RK (2012) Adsorption kinetics for the removal of hazardous dye Congo red by biowaste materials as adsorbents. J Chem 2013:e628582. doi:10.1155/2013/628582
Kaur H, Swati, Kaur R (2014) Kinetic and isotherm studies of Congo red adsorption from aqueous solution by biowaste material. Chem Sci Trans 3:1300–1309. doi:10.7598/cst2014.922
Khadhraoui M, Trabelsi H, Ksibi M et al (2009) Discoloration and detoxicification of a Congo red dye solution by means of ozone treatment for a possible water reuse. J Hazard Mater 161:974–981. doi:10.1016/j.jhazmat.2008.04.060
Khan TA, Sharma S, Khan EA, Mukhlif AA (2014) Removal of Congo red and basic violet 1 by chir pine (Pinus roxburghii) sawdust, a saw mill waste: batch and column studies. Toxicol Environ Chem 96: 555–568. doi:10.1080/02772248.2014.959017
Khanjani S, Morsali A (2014) Ultrasound-promoted coating of MOF-5 on silk fiber and study of adsorptive removal and recovery of haz- ardous anionic dye Bcongo red^. Ultrason Sonochem 21:1424–
1429. doi:10.1016/j.ultsonch.2013.12.012
Konaganti VK, Kota R, Patil S, Madras G (2010) Adsorption of anionic dyes on chitosan grafted poly(alkyl methacrylate)s. Chem Eng J 158:393–401. doi:10.1016/j.cej.2010.01.003
Kondru AK, Kumar P, Chand S (2009) Catalytic wet peroxide oxidation of azo dye (Congo red) using modified Y zeolite as catalyst. J Hazard Mater 166:342–347. doi:10.1016/j.jhazmat.2008.11.042
Kumar PS (2010) Removal of Congo red from aqueous solutions by neem saw dust carbon. Colloid J 72:703–709. doi:10.1134/ S1061933X10050182
Kumar R, Rashid J, Barakat MA (2014) Synthesis and characterization of a starch–AlOOH–FeS2 nanocomposite for the adsorption of Congo red dye from aqueous solution. RSC Adv 4:38334–38340. doi:10. 1039/C4RA05183A
Lachheb H, Puzenat E, Houas A et al (2002) Photocatalytic degradation of various types of dyes (Alizarin S, Crocein Orange G, Methyl Red, Congo Red, Methylene Blue) in water by UV-irradiated titania. Appl Catal B Environ 39:75–90. doi:10.1016/S0926-3373(02) 00078-4
Lahkimi A, Oturan MA, Oturan N, Chaouch M (2006) Removal of textile dyes from water by the electro-Fenton process. Environ Chem Lett 5:35–39. doi:10.1007/s10311-006-0058-x
Lee HU, Lee SC, Lee Y-C et al (2013) Sea-urchin-like iron oxide nano- structures for water treatment. J Hazard Mater 262:130–136. doi:10. 1016/j.jhazmat.2013.08.014
Li J, Xiao X, Xu X et al (2013a) Activated boron nitride as an effective adsorbent for metal ions and organic pollutants. Sci Rep 3:3208. doi: 10.1038/srep03208
Li Y, Cao R, Wu X et al (2013b) Hypercrosslinked poly(styrene-co- divinylbenzene) resin as a specific polymeric adsorbent for purifica- tion of berberine hydrochloride from aqueous solutions. J Colloid Interface Sci 400:78–87. doi:10.1016/j.jcis.2013.03.011
Li H-X, Zhang R-J, Tang L et al (2014a) Use of cassava residue for the removal of Congo red from aqueous solution by a novel process incorporating adsorption and in vivo decolorization. BioResources 9:6682–6698. doi:10.15376/biores.9.4.6682-6698
Li L, Li X, Duan H et al (2014b) Removal of Congo Red by magnetic mesoporous titanium dioxide–graphene oxide core–shell micro- spheres for water purification. Dalton Trans 43:8431. doi:10.1039/ c3dt53474j
Li M, Si Z, Wu X et al (2014c) Facile synthesis of hierarchical porous γ- Al2O3 hollow microspheres for water treatment. J Colloid Interface Sci 417:369–378. doi:10.1016/j.jcis.2013.11.071
Lian L, Guo L, Guo C (2009a) Adsorption of Congo red from aqueous solutions onto Ca-bentonite. J Hazard Mater 161:126–131. doi:10. 1016/j.jhazmat.2008.03.063
Lian L, Guo L, Wang A (2009b) Use of CaCl2 modified bentonite for removal of Congo red dye from aqueous solutions. Desalination 249:797–801. doi:10.1016/j.desal.2009.02.064
Ling Q, Yang M, Li C, Zhang A (2013) Preparation of highly dispersed Ce–Fe bimetallic oxides on graphene and their superior adsorption ability for Congo red. RSC Adv 4:4020–4027. doi:10.1039/ C3RA45924A
Liu Y, Wang W, Wang A (2010) Removal of Congo red from aqueous solution by sorption on organified rectorite. CLEAN – Soil Air Water 38:670–677. doi:10.1002/clen.200900130
Liu D, Lei W, Qin S, Chen Y (2014a) Template-free synthesis of func- tional 3D BN architecture for removal of dyes from water. Sci Rep 4: 4453
Liu F, Xiao L, Kang Z et al (2014b) Adsorption of Congo red by porous TiO2. Chem Ind Eng Prog 33:1321–1326
Liu X, Niu C, Zhen X et al (2015a) Novel approach for synthesis of boehmite nanostructures and their conversion to aluminum oxide nanostructures for remove Congo red. J Colloid Interface Sci 452: 116–125. doi:10.1016/j.jcis.2015.04.037
Liu X, Zhang Z, Shi W et al (2015b) Adsorbing properties of magnetic nanoparticles Mn-ferrites on removal of Congo red from aqueous solution. J Dispers Sci Technol 36:462–470. doi:10.1080/01932691. 2014.896745
Lodha B, Chaudhari S (2007) Optimization of Fenton-biological treat- ment scheme for the treatment of aqueous dye solutions. J Hazard Mater 148:459–466. doi:10.1016/j.jhazmat.2007.02.061
Lorenc-Grabowska E, Gryglewicz G (2007) Adsorption characteristics of Congo Red on coal-based mesoporous activated carbon. Dyes Pigments 74:34–40. doi:10.1016/j.dyepig.2006.01.027
Madrakian T, Afkhami A, Ahmadi M (2012) Adsorption and kinetic studies of seven different organic dyes onto magnetite nanoparticles loaded tea waste and removal of them from wastewater samples. Spectrochim Acta A Mol Biomol Spectrosc 99:102–109. doi:10. 1016/j.saa.2012.09.025
Mahapatra A (2013) Fabrication and characterization of novel iron oxide/ alumina nanomaterials for environmental applications. PhD thesis, NIT, Rourkela, Odisha
Mahapatra A, Mishra BG, Hota G (2013) Adsorptive removal of Congo red dye from wastewater by mixed iron oxide–alumina nanocom- posites. Ceram Int 39:5443–5451. doi:10.1016/j.ceramint.2012.12. 052
Mahmoud MS (2015) Decolorization of certain reactive dye from aque- ous solution using Baker’s yeast (Saccharomyces cerevisiae) strain. HBRC J. doi:10.1016/j.hbrcj.2014.07.005
Maity J, Ray SK (2014) Enhanced adsorption of methyl violet and Congo red by using semi and full IPN of polymethacrylic acid and chitosan. Carbohydr Polym 104:8–16. doi:10.1016/j.carbpol.2013.12.086
Mall ID, Srivastava VC, Agarwal NK, Mishra IM (2005) Removal of Congo red from aqueous solution by bagasse fly ash and activated carbon: kinetic study and equilibrium isotherm analyses. Chemosphere 61:492–501. doi:10.1016/j.chemosphere.2005.03.
065
Mall ID, Srivastava VC, Kumar GVA, Mishra IM ( 2006) Characterization and utilization of mesoporous fertilizer plant waste carbon for adsorptive removal of dyes from aqueous solution. Colloids Surf Physicochem Eng Asp 278:175–187. doi:10.1016/j. colsurfa.2005.12.017
Mandal B, Ray SK (2013) Synthesis of interpenetrating network hydro- gel from poly(acrylic acid-co-hydroxyethyl methacrylate) and sodi- um alginate: modeling and kinetics study for removal of synthetic dyes from water. Carbohydr Polym 98:257–269. doi:10.1016/j. carbpol.2013.05.093
Mandal B, Ray SK (2014) Swelling, diffusion, network parameters and adsorption properties of IPN hydrogel of chitosan and acrylic copol- ymer. Mater Sci Eng C Mater Biol Appl 44:132–143. doi:10.1016/j. msec.2014.08.021
Mane VS, Vijay Babu PV (2013) Kinetic and equilibrium studies on the removal of Congo red from aqueous solution using Eucalyptus
wood (Eucalyptus globulus) saw dust. J Taiwan Inst Chem Eng 44: 81–88. doi:10.1016/j.jtice.2012.09.013
Marsh H, Reinoso FR (2006) Activated carbon. Elsevier, London Mazeau K, Wyszomirski M (2012) Modelling of Congo red adsorption
on the hydrophobic surface of cellulose using molecular dynamics. Cellulose 19:1495–1506. doi:10.1007/s10570-012-9757-6
Mincea M, Patrulea V, Negrulescu A et al (2013) Adsorption of three commercial dyes onto chitosan beads using spectrophotometric de- termination and a multivariate calibration method. J Water Resour Prot 05:446–457. doi:10.4236/jwarp.2013.54044
Mittal A, Mittal J, Malviya A, Gupta VK (2009) Adsorptive removal of hazardous anionic dye BCongo red^ from wastewater using waste materials and recovery by desorption. J Colloid Interface Sci 340:
16–26. doi:10.1016/j.jcis.2009.08.019
Mittal A, Thakur V, Mittal J, Vardhan H (2014) Process development for the removal of hazardous anionic azo dye Congo red from waste- water by using hen feather as potential adsorbent. Desalination Water Treat 52:227–237. doi:10.1080/19443994.2013.785030
Mohammadi A, Daemi H, Barikani M (2014) Fast removal of malachite green dye using novel superparamagnetic sodium alginate-coated Fe3O4 nanoparticles. Int J Biol Macromol 69:447–455. doi:10. 1016/j.ijbiomac.2014.05.042
Mondal S (2008) Methods of dye removal from dye house effluent—an overview. Environ Eng Sci 25:383–396. doi:10.1089/ees.2007.0049 Mumin MA, Khan MMR, Akhter KF, Uddin MJ (2007) Potentiality of open burnt clay as an adsorbent for the removal of Congo red from
aqueous solution. Int J Environ Sci Technol 4:525–532
Murcia MD, Gómez M, Gómez E et al (2011) Photodegradation of Congo red using XeBr, KrCl and Cl2 barrier discharge excilamps: a kinetics study. Desalination 281:364–371. doi:10.1016/j.desal. 2011.08.011
Nagda GK, Ghole VS (2009) Biosorption of Congo red by hydrogen peroxide treated tendu waste. Iran J Environ Health Sci Eng 6: 195–200
Najar-Souissi S, Ouederni A, Ratel A (2005) Adsorption of dyes onto activated carbon prepared from olive stones. J Environ Sci (China) 17:998–1003
Namasivayam C, Arasi DJSE (1997) Removal of Congo red from waste- water by adsorption onto waste red mud. Chemosphere 34:401–417. doi:10.1016/S0045-6535(96)00385-2
Namasivayam C, Kanchana N (1993) Removal of Congo red from aque- ous solution by waste banana pith. Pertanika J Sci Technol 1:33–42 Namasivayam C, Kavitha D (2002) Removal of Congo Red from water by adsorption onto activated carbon prepared from coir pith, an agricultural solid waste. Dyes Pigments 54:47–58. doi:10.1016/
S0143-7208(02)00025-6
Namasivayam C, Sangeetha D (2006) Recycling of agricultural solid waste, coir pith: removal of anions, heavy metals, organics and dyes from water by adsorption onto ZnCl2 activated coir pith carbon. J Hazard Mater 135:449–452. doi:10.1016/j.jhazmat.2005.11.066
Namasivayam C, Yamuna RT (1992) Removal of Congo red from aque- ous solutions by biogas waste slurry. J Chem Technol Biotechnol 53:153–157. doi:10.1002/jctb.280530208
Namasivayam C, Jeyakumar R, Yamuna RT (1994) Dye removal from wastewater by adsorption on Bwaste^ Fe(III)/Cr(III) hydroxide. Waste Manag 14:643–648. doi:10.1016/0956-053X(94)90036-1
Namasivayam C, Muniasamy N, Gayatri K et al (1996) Removal of dyes from aqueous solutions by cellulosic waste orange peel. Bioresour Technol 57:37–43. doi:10.1016/0960-8524(96)00044-2
Neoh CH, Lam CY, Lim CK et al (2015) Biodecolorization of recalcitrant dye as the sole source of nutrition using Curvularia clavata NZ2 and decolorization ability of its crude enzymes. Environ Sci Pollut Res Int 22:11669–11678. doi:10.1007/s11356-015-4436-4
Nimkar DA, Chavan SK (2014) Removal of Congo red dye from aqueous solution by using saw dust as an adsorbent. Int J Eng Res Appl 4:47–51
Nwokem NC, Nwokem CO, Ayuba AA et al (2012) Evaluation of ad- sorptive capacity of natural and burnt kaolinitic clay for removal of Congo red dye. Arch Appl Sci Res 4:939–946
Ogunmodede OT, Ojo AA, Adewole E, Adebayo OL (2015) Adsorptive removal of anionic dye from aqueous solutions by mixture of kaolin and bentonite clay: characteristics, isotherm, kinetic and thermody- namic studies. Iran J Energy Environ 6:147–153. doi:10.5829/idosi. ijee.2015.06.02.11
Öğütveren ÜB, Koparal S (1992) Electrochemical treatment of water
containing dye‐stuffs: anodic oxidation of Congo red and xiron blau 2RHD. Int J Environ Stud 42:41 – 52 . doi: 10.1080/ 00207239208710779
Oladoja NA, Akinlabi AK (2009) Congo red biosorption on palm kernel seed coat. Ind Eng Chem Res 48:6188–6196. doi:10.1021/ ie801003v
Özdemir A, Keskin CS (2009) Removal of a binary dye mixture of Congo red and malachite green from aqueous solutions using a bentonite adsorbent. Clays Clay Miner 57:695–705. doi:10.1346/CCMN. 2009.0570603
Ozmen EY, Yilmaz M (2007) Use of β-cyclodextrin and starch based polymers for sorption of Congo red from aqueous solutions. J Hazard Mater 148:303–310. doi:10.1016/j.jhazmat.2007.02.042
Pal J, Deb MK (2014) Efficient adsorption of Congo red dye from aque- ous solution using green synthesized coinage nanoparticles coated activated carbon beads. Appl Nanosci 4:967–978. doi:10.1007/ s13204-013-0277-y
Pal S, Patra AS, Ghorai S et al (2015) Efficient and rapid adsorption characteristics of templating modified guar gum and silica nanocom- posite toward removal of toxic reactive blue and Congo red dyes. Bioresour Technol 191:291–299. doi:10.1016/j.biortech.2015.04. 099
Panda GC, Das SK, Guha AK (2009) Jute stick powder as a potential biomass for the removal of Congo red and rhodamine B from their aqueous solution. J Hazard Mater 164:374–379. doi:10.1016/j. jhazmat.2008.08.015
Pang YL, Abdullah AZ (2012) Comparative study on the process behav- ior and reaction kinetics in sonocatalytic degradation of organic dyes by powder and nanotubes TiO2. Ultrason Sonochem 19:642–651. doi:10.1016/j.ultsonch.2011.09.007
Park CI, Park OO, Lim JG, Kim HJ (2001) The fabrication of syndiotactic polystyrene/organophilic clay nanocomposites and their properties. Polymer 42:7465–7475. doi:10.1016/S0032-3861(01)00213-0
Paşka O, Ianoş R, Păcurariu C, Brădeanu A (2014) Magnetic nanopowder as effective adsorbent for the removal of Congo Red from aqueous solution. Water Sci Technol 69:1234. doi:10.2166/wst.2013.827
Patel H, Vashi RT (2012) Removal of Congo Red dye from its aqueous solution using natural coagulants. J Saudi Chem Soc 16:131–136. doi:10.1016/j.jscs.2010.12.003
Patil AK, Shrivastava VS (2010) Alternanthera bettzichiana plant powder as low cost adsorbent for removal of Congo red from aqueous solu- tion. Int J ChemTech Res 2:842–850
Pavan FA, Dias SLP, Lima EC, Benvenutti EV (2008) Removal of Congo red from aqueous solution by anilinepropylsilica xerogel. Dyes Pigments 76:64–69. doi:10.1016/j.dyepig.2006.08.027
Pawar RC, Khare V, Lee CS (2014) Hybrid photocatalysts using graphitic carbon nitride/cadmium sulfide/reduced graphene oxide (g-C3N4/ CdS/RGO) for superior photodegradation of organic pollutants un- der UV and visible light. Dalton Trans Camb Engl 2003 43:12514– 12527. doi:10.1039/c4dt01278j
Pearce CI, Lloyd JR, Guthrie JT (2003) The removal of colour from textile wastewater using whole bacterial cells: a review. Dyes Pigments 58:179–196. doi:10.1016/S0143-7208(03)00064-0
Pelekani C, Snoeyink VL (2001) A kinetic and equilibrium study of competitive adsorption between atrazine and Congo red dye on ac- tivated carbon: the importance of pore size distribution. Carbon 39: 25–37. doi:10.1016/S0008-6223(00)00078-6
Peng Y-G, Chen D-J, Ji J-L et al (2013) The preparation of titanium dioxide/palygorskite composite and its application in the adsorption of Congo red. Environ Prog Sustain Energy 32:1090–1095. doi:10. 1002/ep.11717
Ponnusamy SK, Subramaniam R (2013) Process optimization studies of Congo red dye adsorption onto cashew nut shell using response surface methodology. Int J Ind Chem 4:1–10. doi:10.1186/2228- 5547-4-17
Pouretedal HR, Sabzevari S (2011) Photodegradation study of Congo red, methyl orange, methyl red and methylene blue under simulated solar irradiation catalyzed by ZnS/CdS nanocomposite. Desalination Water Treat 28:247–254. doi:10.5004/dwt.2011.1853
Prabu D, Parthiban R, Narendrakumar G (2015) Application of response surface methodology for removal of Congo red dye by nanozerovalent iron impregnated cashew nut shell. J Chem Pharm Res 7:879–884
Purkait MK, Maiti A, DasGupta S, De S (2007) Removal of Congo red using activated carbon and its regeneration. J Hazard Mater 145: 287–295. doi:10.1016/j.jhazmat.2006.11.021
Pushpangadan P, Kaur J, Sharma J (1989) Plantain or edible banana (Musa x paradisica var – sapiemtum) some lesser known folk uses in India. Anc Sci Life 9:20
Raghuvanshi SP, Singh R, Kaushik CP (2008) Adsorption of Congo red dye from aqueous solutions using neem leaves as adsorbent. Asian J Chem 20:4994–5000
Rahimi R, Kerdari H, Rabbani M, Shafiee M (2011) Synthesis, charac- terization and adsorbing properties of hollow Zn-Fe2O4 nano- spheres on removal of Congo red from aqueous solution. Desalination 280:412–418. doi:10.1016/j.desal.2011.04.073
Rai MS, Bhat R, Prajna PS et al (2014) Degradation of malachite green and Congo red using Aloe barabadensis Mill. extract. Int J Curr Microbiol Appl Sci 3:330–340
Rajamohan N (2009) Equilibrium studies on sorption of an anionic dye onto acid activated water hyacinth roots. Afr J Environ Sci Technol 3:399–404. doi:10.5897/AJEST08.192
Rajappa A, K R, B A et al (2014a) Kinetics of adsorption of Congo red onto multiwalled nano carbon. Int J Curr Res Chem Pharm Sci 1:18– 23
Rajappa A, K R, V N (2014b) Removal of Congo red dye from aqueous solution using ZnCl2 activated carbon prepared from Delonix regia pods (flame tree). Int J Chem Pharm Sci 2:961–971
Rajappa A, Ramesh K, Nandhakumar V, Ramesh H (2014c) Kinetics of adsorption of Congo red dye onto commercial activated carbon from aqueous solution. J Environ Nanotechnol 3:43–49. doi:10.13074/ jent.2014.03.142067
Rajappa A, Ramesh K, Nandhakumar V, Ramesh H (2014d) Equilibrium and isotherm studies of Congo red adsorption onto commercial ac- tivated carbon. Int J Curr Res Chem Pharm Sci 1:43–48
Raval NP, Shah PU, Ladha DG et al (2015) Comparative study of chitin and chitosan beads for the adsorption of hazardous anionic azo dye Congo Red from wastewater. Desalination Water Treat 0:1–16. doi: 10.1080/19443994.2015.1027959
Ravi Kumar MNV (2000) A review of chitin and chitosan applications. React Funct Polym 46:1–27. doi:10.1016/S1381-5148(00)00038-9
Reddy MC (2006) Removal of direct dye from aqueous solutions with an adsorbent made from tamarind fruit shell, an agricultural solid waste. J Sci Ind Res 65:443–446
Riede A, Helmstedt M, Riede V et al (2000) In situ polymerized polyaniline films. 2. Dispersion polymerization of aniline in the presence of colloidal silica. Langmuir 16:6240–6244. doi:10.1021/ la991414c
Robinson T, McMullan G, Marchant R, Nigam P (2001) Remediation of dyes in textile effluent: a critical review on current treatment tech- nologies with a proposed alternative. Bioresour Technol 77:247– 255. doi:10.1016/S0960-8524(00)00080-8
Rong X, Qiu F, Qin J et al (2015) A facile hydrothermal synthesis, ad- sorption kinetics and isotherms to Congo Red azo-dye from aqueous solution of NiO/graphene nanosheets adsorbent. J Ind Eng Chem. doi:10.1016/j.jiec.2014.12.009
Safarik I, Rego LFT, Borovska M et al (2007) New magnetically respon- sive yeast-based biosorbent for the efficient removal of water- soluble dyes. Enzyme Microb Technol 40:1551–1556. doi:10. 1016/j.enzmictec.2006.10.034
Safarik I, Horska K, Svobodova B, Safarikova M (2011) Magnetically modified spent coffee grounds for dyes removal. Eur Food Res Technol 234:345–350. doi:10.1007/s00217-011-1641-3
Šafaříková M, Ptáčková L, Kibriková I, Šafařík I (2005) Biosorption of water-soluble dyes on magnetically modified Saccharomyces cerevisiae subsp. uvarum cells. Chemosphere 59:831–835. doi:10. 1016/j.chemosphere.2004.10.062
Saha PD, Chowdhury S, Mondal M, Sinha K (2012) Biosorption of direct red 28 (Congo red) from aqueous solutions by eggshells: batch and column studies. Sep Sci Technol 47:112–123. doi:10.1080/ 01496395.2011.610397
Sakkas VA, Islam MA, Stalikas C, Albanis TA (2010) Photocatalytic degradation using design of experiments: a review and example of the Congo red degradation. J Hazard Mater 175:33–44. doi:10.1016/ j.jhazmat.2009.10.050
Saleh SM, Maarof HI, Rahim SNSA, Nasuha N (2012) Adsorption of Congo red onto bottom ash. J Appl Sci 12:1181–1185. doi:10.3923/ jas.2012.1181.1185
Salleh MAM, Mahmoud DK, Karim WAWA, Idris A (2011) Cationic and anionic dye adsorption by agricultural solid wastes: a comprehen- sive review. Desalination 280:1–13. doi:10.1016/j.desal.2011.07. 019
Sandeman SR, Gun’ko VM, Bakalinska OM et al (2011) Adsorption of anionic and cationic dyes by activated carbons, PVA hydrogels, and PVA/AC composite. J Colloid Interface Sci 358:582–592. doi:10. 1016/j.jcis.2011.02.031
Sarkar D, Bandyopadhyay A (2010) Adsorptive mass transport of dye on rice husk ash. J Water Resour Prot 02:424–431. doi:10.4236/jwarp. 2010.25049
Sarkar AK, Pal A, Ghorai S et al (2014) Efficient removal of malachite green dye using biodegradable graft copolymer derived from amy- lopectin and poly(acrylic acid). Carbohydr Polym 111:108–115. doi: 10.1016/j.carbpol.2014.04.042
Schmidt D, Shah D, Giannelis EP (2002) New advances in polymer/ layered silicate nanocomposites. Curr Opin Solid State Mater Sci 6:205–212. doi:10.1016/S1359-0286(02)00049-9
Selvam K, Swaminathan K, Chae K-S (2003) Decolourization of azo dyes and a dye industry effluent by a white rot fungus Thelephora sp. Bioresour Technol 88:115–119. doi:10.1016/S0960-8524(02) 00280-8
Senthil Kumar P, Ramalingam S, Senthamarai C et al (2010) Adsorption of dye from aqueous solution by cashew nut shell: Studies on equi- librium isotherm, kinetics and thermodynamics of interactions. Desalination 261:52–60. doi:10.1016/j.desal.2010.05.032
Sharma VK (2009) Aggregation and toxicity of titanium dioxide nano- particles in aquatic environment—a review. J Environ Sci Health Part A 44:1485–1495. doi:10.1080/10934520903263231
Sharma J, Janveja B (2008) A study on removal of Congo red dye from the effluents of industry using rice husk carbon activated by steam. Rasayan J Chem 1:936–942
Sharma P, Kaur H, Sharma M, Sahore V (2011) A review on applicability of naturally available adsorbents for the removal of hazardous dyes from aqueous waste. Environ Monit Assess 183:151–195. doi:10. 1007/s10661-011-1914-0
Shasha D, Mupa M, Muzarabani N et al (2015) Removal of Congo red from aqueous synthetic solutions using silica gel immobilized chlor- ophyta Hydrodictyon africanum. J Environ Sci Technol 8:83–90. doi:10.3923/jest.2015.83.90
Shen W, Liao B, Sun W et al (2014) Adsorption of Congo red from aqueous solution onto pyrolusite reductive leaching residue. Desalination Water Treat 52:3564–3571. doi:10.1080/19443994. 2013.855680
Shi W, Xu X, Sun G (1999) Chemically modified sunflower stalks as adsorbents for color removal from textile wastewater. J Appl Polym Sci 71:1841–1850. doi:10.1002/(SICI)1097-4628(19990314) 71:11<1841::AID-APP15>3.0.CO;2-1
Shojamoradi A, Abolghasemi H, Esmaili M et al (2013) Experimental studies on Cong red adsorption by tea waste in presence of silica and Fe2O3 nanoparticle. J Pet Sci Technol 3:25–34
Shrivastava VS (2012) Removal of Congo red dye from aqueous solution by Leucaena eucocephala (Subabul) seed pods. Int J ChemTech Res 4:1038–1043
Shu J, Wang Z, Huang Y et al (2015) Adsorption removal of Congo red from aqueous solution by polyhedral Cu2O nano- particles: kinetics, isotherms, thermodynamics and mechanism analysis. J Alloys Compd 633:338–346. doi:10.1016/j. jallcom.2015.02.048
Singh P, Raizada P, Pathania D, Sharma G (2013) Microwave induced KOH activation of guava peel carbon as an adsorbent for Congo red dye removal from aqueous phase. Indian J Chem Technol 20:305– 311
Sistla S, Chintalapati S (2008) Sonochemical degradation of Congo red. Int J Environ Waste Manag 2:309. doi:10.1504/IJEWM.2008. 018251
Sivakumar V (2014) Removal of Congo red dye using an adsorbent prepared from Martynia annua, L. seeds. Am Chem Sci J 4:424– 442. doi:10.9734/ACSJ/2014/6680
Sivarama Krishna L, Sreenath Reddy A, Muralikrishna A et al (2014) Utilization of the agricultural waste (Cicer arientinum Linn fruit shell biomass) as biosorbent for decolorization of Congo red. Desalination Water Treat 0:1–12. doi:10.1080/19443994.2014. 958540
Sivashankar R, Sathya AB, Vasantharaj K, Sivasubramanian V (2014) Magnetic composite an environmental super adsorbent for dye se- questration—a review. Environ Nanotechnol Monit Manag 1–2:36– 49. doi:10.1016/j.enmm.2014.06.001
Smaranda C, Gavrilescu M, Bulgariu D (2010) Studies on sorption of Congo Red from aqueous solution onto soil. Int J Environ Res 5: 177–188
Solís M, Solís A, Pérez HI et al (2012) Microbial decolouration of azo dyes: a review. Process Biochem 47:1723–1748. doi:10.1016/j. procbio.2012.08.014
Somasekhara Reddy MC, Sivaramakrishna L, Varada Reddy A (2012) The use of an agricultural waste material, Jujuba seeds for the re- moval of anionic dye (Congo red) from aqueous medium. J Hazard Mater 203–204:118–127. doi:10.1016/j.jhazmat.2011.11.083
Sonar SK, Niphadkar PS, Mayadevi S, Joshi PN (2014) Preparation and characterization of porous fly ash/NiFe2O4 composite: promising adsorbent for the removal of Congo red dye from aqueous solution. Mater Chem Phys 148:371–379. doi:10.1016/j.matchemphys.2014. 07.057
Song Z, Chen L, Hu J, Richards R (2009) NiO111 nanosheets as efficient and recyclable adsorbents for dye pollutant removal from wastewa- ter. Nanotechnology 20:275707. doi:10.1088/0957-4484/20/27/ 275707
Srilakshmi C, Saraf R (2016) Ag-doped hydroxyapatite as efficient ad- sorbent for removal of Congo red dye from aqueous solution: syn- thesis, kinetic and equilibrium adsorption isotherm analysis. Microporous Mesoporous Mater 219:134–144. doi:10.1016/j. micromeso.2015.08.003
Srinivasan A, Viraraghavan T (2010) Decolorization of dye wastewaters by biosorbents: a review. J Environ Manag 91:1915–1929. doi:10. 1016/j.jenvman.2010.05.003
Sui G, Liu T, Li J et al (2013) Photocatalytic degradation of dyestuff wastewater with Zn(2+)-TiO2-SiO2 nanocomposite. J Nanosci Nanotechnol 13:3972–3977
Sun G, Xu X (1997) Sunflower stalks as adsorbents for color removal from textile wastewater. Ind Eng Chem Res 36:808–812. doi:10. 1021/ie9603833
Sun Q, Yang L (2003) The adsorption of basic dyes from aqueous solu- tion on modified peat–resin particle. Water Res 37:1535–1544. doi: 10.1016/S0043-1354(02)00520-1
Sun Y, Lin J, Zhan Y (2013) Adsorption of Congo red from aqueous solution on surfactant-modified zeolites with different coverage types: behavior and mechanism. Sep Sci Technol 48:2036–2046. doi:10.1080/01496395.2013.790448
Syed Shabudeen PS, Venckatesh R, Selvam K et al (2006) Adsorption of Congo red dye from aqueous solution using kapok hull carbon. Res J Chem Environ 10:18–26
Szlachta M, Wójtowicz P (2013) Adsorption of methylene blue and Congo red from aqueous solution by activated carbon and carbon nanotubes. Water Sci Technol J Int Assoc Water Pollut Res 68: 2240–2248. doi:10.2166/wst.2013.487
Tadjarodi A, Imani M, Kerdari H (2013) Adsorption kinetics, thermody- namic studies, and high performance of CdO cauliflower-like nano- structure on the removal of Congo red from aqueous solution. J Nanostructure Chem 3:51. doi:10.1186/2193-8865-3-51
Taha DN, Samaka IS (2012) Natural Iraqi palygorskite clay as low cost adsorbent for the treatment of dye containing industrial wastewater. J Oleo Sci 61:729–736. doi:10.5650/jos.61.729
Tang ZX, Chen Y, Xue J, Yue S (2012) Adsorption and removal of Congo red dye from aqueous solution by using nano-Fe3O4. Adv Mater Res 503–504:262–265. doi:10.4028/www.scientific.net/AMR.503-
504.262
Tanthapanichakoon W, Ariyadejwanich P, Japthong P et al (2005) Adsorption–desorption characteristics of phenol and reactive dyes from aqueous solution on mesoporous activated carbon prepared from waste tires. Water Res 39:1347–1353. doi:10.1016/j.watres. 2004.12.044
Tekin D (2014) Photocatalytic degradation kinetics of Congo Red dye in a sonophotoreactor with nanotube. Prog React Kinet Mech 39:249– 261. doi:10.3184/146867814X14043731662747
Tian X, Li C, Yang H et al (2011) Spent mushroom: a new low-cost adsorbent for removal of Congo Red from aqueous solutions. Desalination Water Treat 27:319–326. doi:10.5004/dwt.2011.2152
Tian P, Han X, Ning G et al (2013) Synthesis of porous hierarchical MgO and its superb adsorption properties. ACS Appl Mater Interfaces 5: 12411–12418. doi:10.1021/am403352y
Tie J, Li P, Xu Z et al (2014) Removal of Congo red from aqueous solution using Moringa oleifera seed cake as natural coagulant. Desalination Water Treat 0:1–8. doi:10.1080/19443994.2014. 905980
Toor M, Jin B (2012) Adsorption characteristics, isotherm, kinetics, and diffusion of modified natural bentonite for removing diazo dye. Chem Eng J 187:79–88. doi:10.1016/j.cej.2012.01.089
Tor A, Cengeloglu Y (2006) Removal of Congo red from aqueous solu- tion by adsorption onto acid activated red mud. J Hazard Mater 138: 409–415. doi:10.1016/j.jhazmat.2006.04.063
Torkian L, Ashtiani BG, Amereh E, Mohammadi N (2012) Adsorption of Congo red onto mesoporous carbon material: equilibrium and kinet- ic studies. Desalination Water Treat 44:118–127. doi:10.1080/ 19443994.2012.691789
Tripathi BP, Dubey NC, Stamm M (2013) Functional polyelectrolyte multilayer membranes for water purification applications. J Hazard Mater 252–253:401–412. doi:10.1016/j.jhazmat.2013.02.052
Uti E, Laouedj N, Ahmed B (2011) ZnO-assisted photocatalytic degra- dation of Congo red and benzopurpurine 4B in aqueous solution. J Chem Eng Process Technol. doi:10.4172/2157-7048.1000106
Venkatesh S, Pandey ND, Quaff AR (2014) Decolorization of synthetic dye solution containing Congo red by advanced oxidation process (AOP). ISR J 10–15
Vijayakumar G, Dharmendirakumar M, Renganathan S et al (2009) Removal of Congo red from aqueous solutions by perlite. CLEAN
– Soil Air Water 37:355–364. doi:10.1002/clen.200800228 Vimonses V, Jin B, Chow CWK, Saint C (2009a) Enhancing removal
efficiency of anionic dye by combination and calcination of clay materials and calcium hydroxide. J Hazard Mater 171:941–947. doi:10.1016/j.jhazmat.2009.06.094
Vimonses V, Lei S, Jin B et al (2009b) Adsorption of Congo red by three Australian kaolins. Appl Clay Sci 43:465–472. doi:10.1016/j.clay. 2008.11.008
Vimonses V, Lei S, Jin B et al (2009c) Kinetic study and equilibrium isotherm analysis of Congo Red adsorption by clay materials. Chem Eng J 148:354–364. doi:10.1016/j.cej.2008.09.009
Vimonses V, Jin B, Chow CWK (2010) Insight into removal kinetic and mechanisms of anionic dye by calcined clay materials and lime. J Hazard Mater 177:420–427. doi:10.1016/j.jhazmat.2009.12.049
Wan Ngah WS, Teong LC, Hanafiah MAKM (2011) Adsorption of dyes and heavy metal ions by chitosan composites: a review. Carbohydr Polym 83:1446–1456. doi:10.1016/j.carbpol.2010.11.004
Wang XS, Chen JP (2009a) Biosorption of Congo red from aqueous solution using wheat bran and rice bran: batch studies. Sep Sci Technol 44:1452–1466. doi:10.1080/01496390902766132
Wang XS, Chen JP (2009b) Removal of the azo dye Congo red from aqueous solutions by the marine alga Porphyra yezoensis Ueda. CLEAN – Soil Air Water 37:793–798. doi:10.1002/clen.200900177 Wang L, Wang A (2007a) Adsorption characteristics of Congo Red onto the chitosan/montmorillonite nanocomposite. J Hazard Mater 147:
979–985. doi:10.1016/j.jhazmat.2007.01.145
Wang L, Wang A (2007b) Removal of Congo red from aqueous solution using a chitosan/organo-montmorillonite nanocomposite. J Chem Technol Biotechnol 82:711–720. doi:10.1002/jctb.1713
Wang L, Wang A (2008a) Adsorption properties of Congo Red from aqueous solution onto surfactant-modified montmorillonite. J Hazard Mater 160:173–180. doi:10.1016/j.jhazmat.2008.02.104
Wang L, Wang A (2008b) Adsorption behaviors of Congo red on the N, O-carboxymethyl-chitosan/montmorillonite nanocomposite. Chem Eng J 143:43–50. doi:10.1016/j.cej.2007.12.007
Wang L, Wang A (2008c) Adsorption properties of Congo red from aqueous solution onto N, O-carboxymethyl-chitosan. Bioresour Technol 99:1403–1408. doi:10.1016/j.biortech.2007.01.063
Wang L, Li J, Wang Y, Zhao L (2011a) Preparation of nanocrystalline Fe3
−xLaxO4 ferrite and their adsorption capability for Congo red. J Hazard Mater 196:342–349. doi:10.1016/j.jhazmat.2011.09.032
Wang Z, Han P, Jiao Y et al (2011b) Adsorption of Congo red using ethylenediamine modified wheat straw. Desalination Water Treat 30:195–206. doi:10.5004/dwt.2011.1984
Wang L, Li J, Wang Y et al (2012a) Adsorption capability for Congo red on nanocrystalline MFe2O4 (M = Mn, Fe, Co, Ni) spinel ferrites. Chem Eng J 181–182:72–79. doi:10.1016/j.cej.2011.10.088
Wang Y, Cheng R, Wen Z, Zhao L (2012b) Investigation on the room- temperature preparation and application of chain-like iron flower and its ramifications in wastewater purification. Chem Eng J 203: 277–284. doi:10.1016/j.cej.2012.06.063
Wang C, Zhang Y, Yu L et al (2013a) Oxidative degradation of azo dyes using tourmaline. J Hazard Mater 260:851–859. doi:10.1016/j. jhazmat.2013.06.054
Wang L, Li J, Mao C et al (2013b) Facile preparation of a cobalt hybrid/ graphene nanocomposite by in situ chemical reduction: high lithium storage capacity and highly efficient removal of Congo red. Dalton Trans 42:8070. doi:10.1039/c3dt50333j
Wang L, Li J, Wang Z et al (2013c) Low-temperature hydrothermal syn- thesis of α-Fe/Fe3O4 nanocomposite for fast Congo red removal. Dalton Trans 42:2572. doi:10.1039/c2dt32245e
Wang P, Yan T, Wang L (2013d) Removal of Congo red from aqueous solution using magnetic chitosan composite microparticles. BioResources 8:6026–6043. doi:10.15376/biores.8.4.6026-6043
Wang C, Le Y, Cheng B (2014a) Fabrication of porous ZrO2 hollow sphere and its adsorption performance to Congo red in water. Ceram Int 40:10847–10856. doi:10.1016/j.ceramint.2014.03.078
Wang X, Shi J, Li Z et al (2014b) Facile one-pot preparation of chitosan/ calcium pyrophosphate hybrid microflowers. ACS Appl Mater Interfaces 6:14522–14532. doi:10.1021/am503787h
Wanyonyi WC, Onyari JM, Shiundu PM (2014) Adsorption of Congo red dye from aqueous solutions using roots of Eichhornia crassipes: kinetic and equilibrium studies. Energy Procedia 50:862–869. doi: 10.1016/j.egypro.2014.06.105
Wei Z, Xing R, Zhang X et al (2013) Facile template-free fabrication of hollow nestlike α-Fe2O3 nanostructures for water treatment. ACS Appl Mater Interfaces 5:598–604. doi:10.1021/am301950k
Wu J, Wang J, Li H et al (2013) Designed synthesis of hematite-based nanosorbents for dye removal. J Mater Chem A 1:9837–9847. doi: 10.1039/C3TA11520H
Wu L, Liu Y, Zhang L, Zhao L (2014a) A green-chemical synthetic route to fabricate a lamellar-structured Co/Co(OH)2 nanocomposite exhibiting a high removal ability for organic dye. Dalton Trans Camb Engl 2003 43:5393–5400. doi:10.1039/c3dt53369g
Wu Y, Luo H, Wang H (2014b) Efficient removal of Congo red from aqueous solutions by surfactant-modified hydroxo aluminum/ graphene composites. Sep Sci Technol 49:2700–2710. doi:10. 1080/01496395.2014.942741
Yagub MT, Sen TK, Ang HM (2012) Equilibrium, kinetics, and thermo- dynamics of methylene blue adsorption by pine tree leaves. Water Air Soil Pollut 223:5267–5282. doi:10.1007/s11270-012-1277-3
Yagub MT, Sen TK, Afroze S, Ang HM (2014) Dye and its removal from aqueous solution by adsorption: a review. Adv Colloid Interface Sci 209:172–184. doi:10.1016/j.cis.2014.04.002
Yamaki SB, Barros DS, Garcia CM et al (2005) Spectroscopic studies of the intermolecular interactions of Congo red and tinopal CBS with modified cellulose fibers. Langmuir ACS J Surf Colloids 21:5414– 5420. doi:10.1021/la046842j
Yan T, Wang L (2014) Adsorption of C.I. Reactive Red 228 and Congo Red dye from aqueous solution by amino-functionalized Fe 3 O 4 particles: kinetics, equilibrium, and thermodynamics. Water Sci Technol 69:612. doi:10.2166/wst.2013.745
Yang L-X, Zhu Y-J, Tong H et al (2007) Hierarchical β-Ni(OH)2 and NiO carnations assembled from nanosheet building blocks. Cryst Growth Des 7:2716–2719. doi:10.1021/cg060530s
Yang Y, Wang G, Wang B et al (2011) Biosorption of Acid Black 172 and Congo Red from aqueous solution by nonviable Penicillium YW 01: kinetic study, equilibrium isotherm and artificial neural network modeling. Bioresour Technol 102:828–834. doi:10.1016/j.biortech. 2010.08.125
Yang X, Wang Z, Jing M et al (2013) Efficient removal of dyes from aqueous solution by mesoporous nanocomposite Al2O3/ Ni0.5Zn0.5Fe2O4 microfibers. Water Air Soil Pollut 225:1–12. doi:10.1007/s11270-013-1819-3
Yang L, Zhang Y, Liu X et al (2014a) The investigation of synergistic and competitive interaction between dye Congo red and methyl blue on magnetic MnFe2O4. Chem Eng J 246:88–96. doi:10.1016/j.cej. 2014.02.044
Yang X, Shen X, Jing M et al (2014b) Removal of heavy metals and dyes by supported nano zero-valent iron on barium ferrite microfibers. J Nanosci Nanotechnol 14:5251–5257. doi:10.1166/jnn.2014.8687
Yang R-X, Wang T-T, Deng W-Q (2015) Extraordinary capability for water treatment achieved by a perfluorous conjugated microporous polymer. Sci Rep 5:10155. doi:10.1038/srep10155
Yao Y, Miao S, Liu S et al (2012) Synthesis, characterization, and adsorp- tion properties of magnetic Fe3O4@graphene nanocomposite. Chem Eng J 184:326–332. doi:10.1016/j.cej.2011.12.017
Yermiyahu Z, Lapides I, Yariv S (2003) Visible absorption spectroscopy study of the adsorption of Congo Red by montmorillonite. Clay Miner 38:483–500. doi:10.1180/0009855033840110
Yu C, Dong X, Guo L et al (2008) Template-free preparation of mesopo- rous Fe2O3 and its application as absorbents. J Phys Chem C 112: 13378–13382. doi:10.1021/jp8044466
Yu X, Wei C, Ke L et al (2010) Development of organovermiculite-based adsorbent for removing anionic dye from aqueous solution. J Hazard Mater 180:499–507. doi:10.1016/j.jhazmat.2010.04.059
Yu L, Xue W, Cui L et al (2014) Use of hydroxypropyl-β-cyclodextrin/ polyethylene glycol 400, modified Fe3O4 nanoparticles for Congo red removal. Int J Biol Macromol 64:233–239. doi:10.1016/j. ijbiomac.2013.12.009
Yu J, Zhu J, Feng L, Chi R (2015) Simultaneous removal of cationic and anionic dyes by the mixed sorbent of magnetic and non-magnetic modified sugarcane bagasse. J Colloid Interface Sci 451:153–160. doi:10.1016/j.jcis.2015.04.009
Zaini MAA, Zakaria M, Mohd Setapar SH, Che-Yunus MA (2013) Sludge-adsorbents from palm oil mill effluent for methylene blue removal. J Environ Chem Eng 1:1091–1098. doi:10.1016/j.jece. 2013.08.026
Zaini MAA, Cher TY, Zakaria M et al (2014) Palm oil mill effluent sludge ash as adsorbent for methylene blue dye removal. Desalination Water Treat 52:3654–3662. doi:10.1080/19443994.2013.854041
Zehra T, Priyantha N, Lim LBL, Iqbal E (2015) Sorption characteristics of peat of Brunei Darussalam V: removal of Congo red dye from aqueous solution by peat. Desalination Water Treat 54:2592–2600. doi:10.1080/19443994.2014.899929
Zenasni MA, Meroufel B, Merlin A, George B (2014) Adsorption of Congo red from aqueous solution using CTAB-kaolin from Bechar Algeria. J Surf Eng Mater Adv Technol 04:332–341. doi:10.4236/ jsemat.2014.46037
Zeng L-X, Chen Y-F, Zhang Q-Yet al (2014) Adsorption of Congo red by cross-linked chitosan resins. Desalination Water Treat 52:7733– 7742. doi:10.1080/19443994.2013.833879
Zhai Y, Zhai J, Zhou M, Dong S (2009) Ordered magnetic core–manga- nese oxide shell nanostructures and their application in water treat- ment. J Mater Chem 19:7030–7035. doi:10.1039/B912767D
Zhai T, Xie S, Lu X et al (2012) Porous Pr(OH)3 nanostructures as high- efficiency adsorbents for dye removal. Langmuir ACS J Surf Colloids 28:11078–11085. doi:10.1021/la3013156
Zhan Y-H, Lin J-W (2013) Adsorption of Congo red from aqueous solu- tion on hydroxyapatite. Huan Jing Ke Xue Huanjing Kexue Bian Ji Zhongguo Ke Xue Yuan Huan Jing Ke Xue Wei Yuan Hui Huan Jing Ke Xue Bian Ji Wei Yuan Hui 34:3143–3150
Zhang G, Zhao L (2013) Synthesis of nickel hierarchical structures and evaluation on their magnetic properties and Congo red removal abil- ity. Dalton Trans Camb Engl 2003 42:3660–3666. doi:10.1039/ c2dt32268d
Zhang Z, Shan Y, Wang J et al (2007) Investigation on the rapid degra- dation of Congo red catalyzed by activated carbon powder under microwave irradiation. J Hazard Mater 147:325–333. doi:10.1016/j. jhazmat.2006.12.083
Zhang Z, Moghaddam L, O’Hara IM, Doherty WOS (2011) Congo Red adsorption by ball-milled sugarcane bagasse. Chem Eng J 178:122– 128. doi:10.1016/j.cej.2011.10.024
Zhang X, Gong J, Zeng G, Deng J (2013) Synthesis of magnetic graphene oxide adsorbent for Congo red removal from aqueous solution. China Environ Sci 33:1379–1385
Zhang W, Zhao W, Zhou Z, Yang Z (2014a) Facile synthesis of α-MnO2 micronests composed of nanowires and their enhanced adsorption to Congo red. Front Chem Sci Eng 8:64–72. doi:10.1007/s11705-014- 1402-5
Zhang X, Zhang Y, Wang D, Qu F (2014b) Investigation of adsorption behavior of Cu2O submicro-octahedra towards Congo red. J Nanomater 2014:e619239. doi:10.1155/2014/619239
Zhao YH, Wang L (2012) Adsorption characteristics of Congo red from aqueous solution on the carboxymethylcellulose/montmorillonite nanocomposite. Adv Mater Res 450–451:769–772. doi:10.4028/ www.scientific.net/AMR.450-451.769
Zhao Z, Wang X, Zhao C et al (2010) Adsorption and desorption of antimony acetate on sodium montmorillonite. J Colloid Interface Sci 345:154–159. doi:10.1016/j.jcis.2010.01.054
Zhao B, Shang Y, Xiao W et al (2014a) Adsorption of Congo red from solution using cationic surfactant modified wheat straw in column model. J Environ Chem Eng 2:40–45. doi:10.1016/j.jece.2013.11. 025
Zhao X, Wang W, Zhang Yet al (2014b) Synthesis and characterization of gadolinium doped cobalt ferrite nanoparticles with enhanced ad- sorption capability for Congo Red. Chem Eng J 250:164–174. doi: 10.1016/j.cej.2014.03.113
Zhao Y, Chen H, Li J, Chen C (2015) Hierarchical MWCNTs/Fe3O4/ PANI magnetic composite as adsorbent for methyl orange removal. J Colloid Interface Sci 450:189–195. doi:10.1016/j.jcis.2015.03.015
Zhou MH, Lei LC (2006) Electrochemical regeneration of activated car- bon loaded with p-nitrophenol in a fluidized electrochemical reactor. Electrochim Acta 51:4489–4496. doi:10.1016/j.electacta.2005.12. 028
Zhu H-Y, Fu Y-Q, Jiang R et al (2011) Adsorption removal of Congo red onto magnetic cellulose/Fe3O4/activated carbon composite: equilib- rium, kinetic and thermodynamic studies. Chem Eng J 173:494– 502. doi:10.1016/j.cej.2011.08.020
Zhu H-Y, Fu Y-Q, Jiang R et al (2012a) Novel magnetic chitosan/poly(- vinyl alcohol) hydrogel beads: preparation, characterization and ap- plication for adsorption of dye from aqueous solution. Bioresour Technol 105:24–30. doi:10.1016/j.biortech.2011.11.057
Zhu H, Zhang M, Liu Yet al (2012b) Study of Congo red adsorption onto chitosan coated magnetic iron oxide in batch mode. Desalination Water Treat 37:46–54. doi:10.1080/19443994.2012.661252
Zuas O, Kristiani A, Haryono A (2015) Synthesis of the nano structured zinc oxide using the soft template of Cylea barbata miers extract and its promising property for dye adsorbent. J Adv Mater Process 3:39–50
Zulfikar MA, Setiyanto H (2013) Adsorption of Congo red from aqueous solution using powdered eggshell. Int J ChemTech Res 5:1532– 1540
Zulfikar MA, Setiyanto H, Rusnadi SL (2014) Rubber seeds (Hevea brasiliensis): an adsorbent for adsorption of Congo red from aqueous solution. Desalination Water Treat 0:1–12. doi:10.1080/19443994. 2014.966276