Banana Peel: A Green Solution for Metal Removal from Contaminated Waters
Banana Peel: A Green Solution for Metal Removal from Contaminated Waters
Korean Journal of Environmental Agriculture. 2013. Jun, 32(2): 108-116
Copyright © 2013, The Korean Society of Environmental Agriculture
This is an Open-Access article distributed under the terms of the Creative Commons Attribution Non-Commercial License ( which permits unrestricted non-commercial use, distribution, and reproduction in any medium, provided the original work is properly cited.
  • Received : March 19, 2013
  • Accepted : June 11, 2013
  • Published : June 30, 2013
Export by style
Cited by
About the Authors
KKIU Arunakumara
Department of Crop Science, Faculty of Agriculture, University of Ruhuna, Kamburupitiya, Sri Lanka
Buddhi Charana Walpola
Department of Bio-Environmental Chemistry, College of Agriculture and Life Sciences, Chungnam National University, Daejeon, 305-764, Korea
Min-Ho Yoon
Department of Bio-Environmental Chemistry, College of Agriculture and Life Sciences, Chungnam National University, Daejeon, 305-764, Korea

Certain crop-based waste materials have been recognized as cost-effective and highly efficient adsorbents for removal and recovery of different kind of heavy metals from aqueous solutions. The ability is strongly attributed to the carboxyl functional group of some pectin substances such as galacturonic acid often found in fruit peels. The present manuscript was aimed at assessing the potential applicability of banana peel for metal removal from contaminated waters.
As revealed by laboratory investigations, banana peel contains pectin (10-21%), lignin (6-12%), cellulose (7.6-9.6%), and hemicelluloses (6.4-9.4%). The pectin extraction is reported to have glucose, galactose, arabinose, rhamnose, xylose, and galactouroninc acid. Several studies conducted under different conditions proved that banana peel is capable of adsorbing 5.71, 2.55, 28.00, 6.88, 7.97, and 5.80 mg/g of Cd 2+ , Co 2+ , Cu 2+ , Ni 2+ , Pb 2+ , and Zn 2+ , respectively, from aqueous solutions. Adsorption capacity is, however, dependent upon several factors including solution pH, dose of adsorbent and metal concentration, contact time and shaking speed.
Since the annual world production of banana exceeds 100 million tons, about 40 million tons of banana peel (40% of total weight of the fresh fruit) remains vastly unused. Exploring a sound technology with banana peel would therefore, not only address the much needed sustainable tool for cleaning contaminated waters, but of course bring an additional value to the banana industry worldwide.
Metal contamination is considered to be one of the most ubiquitous and complex environmental issues today. Accumulation of heavy metals in soils and water is of particularly important because it can impact upon human health through possible contamination of food ( Sadon ., 2012 ). With the increasing demand for water for agricultural, domestic, industrial, and recreational purposes, remediation and reuse of contaminated waters receive prime attention globally ( Opeolu and Fatoki, 2012 ). Different technologies, such as adsorption, chemical precipitation, coagulation/ flocculation, evaporation, complexation, membrane filtration, biological operations, electrochemical operations, ion exchange/solvent extraction, etc., have been employed in removing metals from contaminated water and wastewater. Due to the inherent merits such as easy handling, minimal sludge production, and regeneration capability, etc., associated with adsorption, it has been widely used as an efficient and effective technique for heavy metal removal ( Chiban ., 2012 ; Pagnanelli ., 2003 ). However, the success of this technique is heavily dependent upon the nature of the adsorbent material used for the process. Recently, activated carbon is extensively used as the adsorbent, though the cost involved with the initial establishment and the regeneration system is relatively high ( Aktas and Cecen, 2007 ). Therefore, the search for economically affordable alternatives remains one of the key priorities among researches.
In this context, agricultural waste materials have been recognized as possible alternative adsorbents mainly due to the fact that they are easily available, cost-effective and highly efficient in adsorbing different kind of heavy metal ions ( Montanher ., 2005 ; Nasernejad ., 2005 ). In fact, certain widely available plant materials remain unused resources, thus the use of them could indeed be an environmentally friendly approach too ( Ashraf ., 2011 ). Various plant-based adsorbent agents have been tested under different conditions, such as seaweed ( Basha ., 2008 ; Hashim and Chu, 2004 ), marine algal biomass ( Sheng ., 2004 ), seafood processing waste sludge ( Lee and Davis, 2001 ), sugar beet pulp ( Reddad ., 2002b ), banana peel ( Ashraf ., 2011 ; Castro ., 2011 ; Hossain ., 2012 ), papaya wood ( Saeed ., 2005 ), grape stalk wastes ( Villaescusa ., 2004 ), neem bark ( King ., 2007 ), neem biomass ( Arshad ., 2008 ), tea-waste ( Malkoc and Nuhoglu, 2007 ; Kamsonlian ., 2011a ), sawdust ( Garg ., 2004 ; Memon ., 2005 ), tamarind bark ( Prasad and Abdulsalam, 2009 ), tamarind hull ( Verma ., 2006 ), potato peel waste ( Ahalya ., 2005 ), maize corn cob, jatropha oil cake, sugarcane bagasse ( Garg ., 2007 ), rice husk ( Kumar and Bandyopadhyay, 2006 ), rice straw ( Gao ., 2008 ), wheat straw ( Robinson ., 2002 ), wheat shells ( Bulut ., 2007 ), wheat bran ( Sulak ., 2006 ), maize leaf ( Babarinde ., 2006 ), wood and bark ( Mohan ., 2007 ), teak leaf powder ( King ., 2006 ), rubber leaf powder ( Hanafiah ., 2006 ), pine bark ( Al-Asheh ., 2000 ), saltbush ( Sawalha ., 2005 ), and olive pomace ( Pagnanelli ., 2003 ), orange peel ( Kamsonlian ., 2011b ), etc. By contrast, many crop residues are reported to be excellent adsorbents ( Table 1 ) with good adsorption capacity better than activated carbons and commercial ion exchangers. However, the use of them in their original forms is not yet fully exploited ( Anirudhan and Shibi, 2007 ). Moreover, many of the studies have been conducted with particular type of wastes with specific aqueous-phase applications. The present paper reviews literature dedicated to use of banana peel in removal of heavy metals from waters.
Crop-based waste materialsas metal adsorbents in aqueous mediums
PPT Slide
Lager Image
Crop-based waste materialsas metal adsorbents in aqueous mediums
Banana peel as a metal adsorbent
Banana is one of the most popular fruit crops grown in more than 130 countries, particular in tropical and sub-tropical regions of the world. The crop is grown by small-and large-scale producers alike and the annual world banana production exceeds 100 million tons ( UNCTAD, 2012 ). Though the vast majority (over 90%) of the production is auto-consumed, a portion worth about $ 8 billion is still traded internationally, which shows an almost steady annual growth rate ( UNCTAD, 2012 ).
Banana peel, which represents about 40% of total weight of the fresh fruit ( Anhwange ., 2008 ) is generally considered to be a waste material. As of the production records mentioned above, it is apparent that the banana industry produces more than 40 million tons of banana peel annually (peel represents about 40% of the total weight of fresh banana). Exploring alternative uses of banana peel would thus bring an additional value to the industry.
Fruit peels generally contain organic compounds such as cellulose, hemicellulose, pectin substances, chlorophyll pigments, and some other low molecular weight compounds ( Xiaomin ., 2007 ). The pectin substances, a complex heteropolysaccharides containing galacturonic acid, arabinose, galactose, and rhamnose, are found in fruit peels ( Reddad ., 2002a ). Galacturonic acid with the carboxyl functions could make pectin substances a strong metal adsorbent in aqueous solutions ( Saeed ., 2005 ). As reported by Mohapatra . (2010) , banana peel is found to be a good source of pectin (10-21%), lignin (6-12%), cellulose (7.6-9.6%), hemicelluloses (6.4-9.4%), and galactouroninc acid. Furthermore the pectin extracted from banana peel also contains glucose, galactose, arabinose, rhamnose, and xylose ( Emaga ., 2008 ).
Under this background, banana peel is recognized to be an economically viable and environmentally sound adsorbent for removal of heavy metals from contaminated waters. According to Hossain (2012) , 1g of banana peel can adsorb 28 mg of Cu 2+ in a favourable condition, and thus provides with a potential alternative of Cu 2+ removal from water. Moreover, it could adsorb 5.71 and 2.18 mg/g of Cd 2+ and Pb 2+ , respectively ( Anwar , 2010 ). Annadurai (2002) studied the adsorption capacity of divalent heavy metal ions (Cu 2+ , Zn 2+ , Co 2+ , Ni 2+ and Pb 2+ ) onto acid (HNO 3 ) and alkali (NaOH) treated banana peels. According to them, the adsorption capacity was in the order of Pb 2+ > Ni 2+ > Zn 2+ > Cu 2+ > Co 2+ . The maximum metal adsorptions were recorded as 7.97 (Pb 2+ ), 6.88 (Ni 2+ ), 5.80 (Zn 2+ ), 4.75 (Cu 2+ ), and 2.55 mg/g (Co 2+ ). Memon (2008b) assessed the practical applicability of banana peel to remove arsenic from contaminated water samples collected from 8 different areas of Sindh, Pakistan. They collected 100 mL of water samples, filtered and mixed with the banana peel before being shaken for 30 min. The contents of arsenic in the solution were measured before and after adsorption and results revealed that 98-100% of arsenic can be removed successfully using the banana peel. However, successful metal removal can be achieved only if due attention is paid on the followings.
Solution pH
The pH of the medium is considered to be a key factor governing the process of metal adsorption from an aqueous solution ( Shafaghat , 2012 ). The solution pH is capable of influencing the dissociation state of the adsorbents, ionic state of functional groups and species of metals ( Hossain , 2012 ). As reported by Fiol (2006) , the effect of pH on solution chemistry of the target metal includes hydrolysis, complexation by organic and/or inorganic ligands and redox potentials. At elevated pH values, adsorption is reduced due to high precipitation, ion exchange and aqueous metal hydroxide formation ( Shafaghat , 2012 ). Furthermore, under basic condition, the binding sites may not activate as in acidic medium ( Memon , 2008a ). Analogous to these reports, Demirbas (2009) reported that at high pH, copper began to precipitate as Cu(OH) 2 + , resulting in lower adsorption. Hossain (2012) also observed gradual reduction in Cu 2+ adsorption onto banana peel when solution pH increased. According to them, Cu 2+ adsorption capacity was declined when pH decreased below 2.0. However, it was reported to increase with the increase in pH from 2.0 to 6.0 ( Hossain , 2012 ). As observed by Wang and Qin (2005) , under slightly acidic conditions, Cu 2+ is the dominant free species involved in adsorption. In fact, at slightly acidic conditions, linked H + is released from the active sites allowing metals ions to be absorbed. However, when pH was further lowered, H 3 O + ions begin to compete with Cu 2+ for binding onto adsorbent sites resulting in poor adsorption capacity ( Demirbas , 2009 ). Similar observations were made by Kaewsarn (2008) who studied the Cd 2+ biosorption onto banana peel. According to them, though the biosorption at very highly acidic condition (pH 1.0) was negligible, removal of Cd 2+ increased with increasing pH from 1.0 to 5.0. In this regard, Shafaghat (2012) reported that under highly acidic conditions, formation of links between metal ions and the active site is restricted by the excessive protonation of the active sites which ultimately results in lower adsorption. However, contrary to this Memon (2008b) reported that adsorption of arsenic species is independent of pH, which of course raises the practical applicability of banana peel to remove arsenic from contaminated waters.
Contact time
Hossain . (2012) , based on the results of their study, reported that Cu 2+ adsorption onto banana peel was relatively quicker than those reported for some other bio-adsorbents. They observed a rapid adsorption during the first 30 min, followed by a constant rate of Cu 2+ removal for further 30 min before reached the equilibrium. In the case of arsenic, Memon (2008b) reported that the equilibrium was established within 30 min, and 75% and 95% sorption was recorded for As(III) and As(V), respectively. According to them, no significant increase in the percent sorption onto banana peel was observed after 30 min. When particles of banana peel were introduced to the solution, metal ions could find flurry of vacant active binding sites resulting in rapid initial adsorption. This was further confirmed by Shafaghat . (2012) , who studied the adsorption of Pb 2+ , Cu 2+ , and Cr 3+ by five plant materials. According to them, the maximum removal of three metals was attained after a shaking period of 90 min. Once the majority of binding sites were occupied, formation of repulsive forces between the metal ions on the solid surface and the liquid phase makes it difficult for further binding to the remaining vacant surface sites ( Achak ., 2009 ; Srivastava ., 2006 ). Thus, the adsorption of metal ions gradually decreases as time progressed. In fact, in order to bind, the metal ions have to pass through the deeper surface of the pores, which of course encounter substantial resistance leading to deceased adsorption during the later phase of adsorption ( Srivastava ., 2006 ). As stated by Shafaghat . (2012) , the transportation rate of ions from the exterior to the interior sites of the adsorbent particles actually determines the adsorption rate of later phase.
Doses and particle size
It is well understood that the amount of metal removal is vastly dependent upon the metal concentration in the solution. As reported by Chojnacka (2006) , who studied the effect of initial concentration of Cr 3+ on adsorption by wheat straw, the adsorption rate was increased with the increase in the initial metal ion concentration. However, if the amount of biomass remains constant in the system, the metal removal efficiency may be reduced regardless the increased metal concentration ( Zhou ., 2007 ). Furthermore, Hossain . (2012) who studied the Cu 2+ adsorption by banana peel reported that the adsorbent dose is also decisive for metal removal. They observed the highest Cu 2+ removal (88%) when the initial Cu 2+ concentration of 10 mg/L with the adsorbent dose of 5 g/L. Similar investigation was conducted by Anwar . (2010) to study the effect of adsorbent dosage on the adsorption of Cd 2+ and Pb 2+ . They used different dosages of banana peel ranging 10-90 g/L, and the maximum removal was observed at the doses of 30 and 40 g/L, respectively, for Cd 2+ (89.2%) and Pb 2+ (85.3%). At the high doses of adsorbent, removal of metal may be affected by the partial aggregation among the available active binding sites ( Anwar ., 2010 ), whereas at low doses, lack of active binding sites may result in lower rate of metal removal ( Karthikeyan ., 2007 ).
Kaewsarn . (2008) used dried biosorbent derived from banana peel to study the removal of Cd 2+ from aqueous solution and reported that particle size of banana peel had no effect on the removal of metal ions, which is analogous to Volesky (2003) who studied the effect of particle size on uranium and cadmium biosorption by Sargassum biomass. They used three sizes of biomass (0.5-0.7 mm, 1.0-1.4 mm and native whole seaweed for uranium; 0.5-0.7 mm, 0.84-1.00 mm and 1.0-1.4 mm for cadmium). According to them, no significant difference in sorption rate for the metals among the tested particle sizes was observed. Cossich . (2002) , based on their finding with biosorption of chromium onto Sargassum biomass also reported that the rate of biosorption was independent from the particle size of the biomass. Kaewsarn . (2008) further stated that the higher biosorption level achieved by smaller particle size of the biosorbents may not be connected to the fact that smaller particle sizes give large surface areas. However, adsorption is considered to be a surface phenomenon; thus sorbents with higher surface area should exhibit a rapid adsorption than that of sorbents with lower surface area. Furthermore, as stated by Daifullah . (2004) , the smaller particles do have higher specific surface area and low mass transfer resistance than the larger biosorbents. In fact, Daifullah . (2004) observed higher adsorption rate and uptake from the smaller and fine particles of the activated carbon adsorbent prepared from biomass than the larger particles of the same adsorbent. Demirbas . (2004) also have reported that the equilibrium might be achieved quickly if smaller particles were used. According to Park . (2010) , smaller particles are better suited for a batch type removal setup due to the higher surface area of the biosorbent, however, not for column processes due to its low mechanical strength and clogging of the column. A wide range of particle sizes including 5 x 5 mm, 3 x 3 mm, 2 x 2 mm, 1 x1 mm, fine powder (<150 μm), semi-fine powder (150-300 μm), middle size powder (300-420 μm), semi-coarse size powder (420-600 μm), and coarse powder (600-900 μm) was used to study the effect of particle size of banana peel on the adsorption of Cu 2+ ( Liu ., 2012 ). Based on the findings, they claimed that Cu 2+ removal efficiency of powder particles is much higher than that of in larger sized particles. However, they observed no significant differences among different sized powder particles. As reported by Kaewsarn . (2008) , ground particles irrespectively their sizes, make similar thickness of adsorbents, thus the effect of particle size was hard to observe. Contradicted reports on the effect of particle size might be due to the different experimental conditions under which above investigations have been conducted.
Other factors
Hossain . (2012) studied the effect of shaking speed (30-200 rpm) on the adsorption of Cu 2+ by banana peel. Both at low and high speeds, the rate of Cu 2+ adsorption decreased and the maximum adsorption (88%) was recorded at near 120 rpm. At low speed, particles could not spread adequately for providing active binding sites for adsorption of metal, while at high speed, vigorously spreading the particles did not allow sufficient time to bind with metal ions ( Anwar ., 2010 ).
Banana peel has to be dried before being used as adsorbent. The effect of drying temperature on the metal removal efficiency was tested with various drying temperatures (30, 60, 90, 105, 120, and 150℃) ( Liu ., 2012 ). Based on the results, they reported that banana peel dried at higher temperature is more effective in removing Cu 2+ than those dried at lower temperatures. As a possible explanation, they claimed that higher temperature could change the interaction area between the ligands on the cell wall and the metal ions through expanding the surface area of the adsorbents. However, taking the energy consumption for drying also into account, they suggested 120℃ as the most reasonable temperature for drying banana peels.
Based on the scale of production, banana peel could certainly be recognized as a promising crop-based material available for exploring alternative uses. The proven metal removal capacity of banana peel provides with a favorable platform to researchers to work on and to come out with a sound technology applicable in removal and recovery of metals from water and wastewaters. Such a green technology would not only address the much needed sustainable tool for cleaning contaminated waters, but of course bring an additional value to banana peel enhancing the fruit industry worldwide.
Achak M. , Hafidi A. , Ouazzani N. , Sayadic S. , Mandi L. 2009 Low cost biosorbent banana peel for the removal of phenolic compounds from olive mill wastewater: Kinetic and equilibrium studies J. Hazard. Mater. 166 117 - 125    DOI : 10.1016/j.jhazmat.2008.11.036
Ahalya N. , Kanamadi R.D. , Ramachandra T.V. 2005 Biosorption of chromium(VI) from aqueous solution by the husk Bengal gram (Cicer arientinum) Electron. J. Biotechnol. 8 258 - 264    DOI : 10.2225/vol8-issue3-fulltext-10
Aktas O. , Cecen F. 2007 Adsorption, desorption and bioregeneration in the treatment of 2-chlorophenol with activated carbon J. Hazard. Mater. 141 769 - 777    DOI : 10.1016/j.jhazmat.2006.07.050
Al-Asheh S. , Banat F. , Al-Omari R. , Duvnjak Z. 2000 Predictions of binary sorption isotherms for the sorption of heavy metals by pine bark using single isotherm data Chemosphere 41 659 - 665    DOI : 10.1016/S0045-6535(99)00497-X
Anhwange B.A. , Ugye T.J. , Nyiaatagher T.D. 2008 Chemical composition of Musa sapientum (banana) peels Electron. J. Environ. Agric. Food Chem. 8 437 - 442
Anirudhan T.S. , Shibi I.G. 2007 Preparation of a cation exchanger containing carboxyl groups from banana stalk and its utilization as chelating agent InfoMusa 16 7 - 11
Annadurai G. , Juang R.S. , Lee D.J. 2002 Adsorption of heavy metal from water using banana and orange peels Water Sci. Technol. 47 185 - 190
Anwar J. , Shafique U. , Zaman W. , Salman M. , Dar A. , Anwar S. 2010 Removal of Pb(II) and Cd(II) from water by adsorption on peels of banana Bioresour. Technol. 101 1752 - 1755    DOI : 10.1016/j.biortech.2009.10.021
Arshad M. , Zafar M.N. , Younis S. , Nadeem R. 2008 The use of neem biomass for the biosorption of zinc from aqueous solutions J. Hazard. Mater. 157 534 - 540    DOI : 10.1016/j.jhazmat.2008.01.017
Ashraf M.A. , Mahmood K. , Wajid A. 2011 Study of low cost biosorbent for biosorption of heavy metals IACSIT Press Singapoore Proceedings of the International Conference on Food Engineering and Biotechnology, IPCBEE 9 60 - 68
Babarinde N.A.A. , Oyebamiji B.J. , Adebowale S.R. 2006 Biosorption of lead ions from aqueous solution by maize leaf Int. J. Phys. Sci. 1 23 - 26
Basha S. , Murthy Z.V.P. , Jha B. 2008 Biosorption of hexavalent chromium by chemically modified seaweed Cystoseira indica. Chem. Eng. J. 137 480 - 488
Bulut Y. , Gozubenli N. , Aydin H. 2007 Equilibrium and kinetics studies for adsorption of direct blue 71 from aqueous solution by wheat shells J. Hazard. Mater. 144 300 - 306    DOI : 10.1016/j.jhazmat.2006.10.027
Castro R.S.D. , Caetano L. , Ferreira G. , Padilha P.M. , Saeki M.J. , Zara L.F. , Martines A.M.U. , Castro G.R. 2011 Banana peel applied to the solid phase extraction of copper and lead from river water: Pre-concentration of metal ions with a fruit waste Ind. Eng. Chem. Res. 50 3446 - 3451    DOI : 10.1021/ie101499e
Chiban M. , Zerbet M. , Carja G. , Sinan F. 2012 Application of low-cost adsorbents for arsenic removal: A review J. Environ. Chem. Ecotoxicol. 4 91 - 102
Chojnacka K. 2006 Biosorption of Cr(III) ions by wheat straw and grass: a systematic characterization of new biosorbents Pol. J. of Environ. Stud. 15 845 - 852
Cossich E.S. , Tavares C.R.G. , Ravagnani T.M.K. 2002 Biosorption of chromium(III) by Sargassum sp. biomass Electron. J. Biotechnol. 5 133 - 137
Daifullah A.A.M. , Girgis B.S. , Gad H.M.H. 2004 A study of the factors affecting the removal of humic acid by activated carbon prepared from biomass material Coll. Surf. 235 1 - 10    DOI : 10.1016/j.colsurfa.2003.12.020
Demirbas E. , Kobya M. , Senturkl E. , Ozkan T. 2004 Adsorption kinetics for the removal of chromium(VI) from aqueous solution on the activated carbons prepared from agricultural wastes J. Water SA. 30 533 - 539
Demirbas E. , Dizge N. , Sulak M.T. , Kobya M. 2009 Adsorption kinetics and equilibrium of copper from aqueous solutions using hazelnut shell activated carbon Chem. Eng. J. 148 480 - 487    DOI : 10.1016/j.cej.2008.09.027
Emaga T.H. , Robert C. , Ronkart S.N. , Wathelet B. , Paquot M. 2008 Dietary fibre components and pectin chemical features of peels during ripening in banana and plantain varieties Bioresour. Technol. 99 4346 - 4354    DOI : 10.1016/j.biortech.2007.08.030
Fiol N. , Villaescusa I. , Martinez M. 2006 Sorption of Pb(II), Ni(II), Cu(II), and Cd(II) from aqueous solution by olive stone waste J. Sep. Purif Technol. 50 132 - 140    DOI : 10.1016/j.seppur.2005.11.016
Gao H. , Liu Y. , Zeng G. , Xu W. , Li T. , Xia W. 2008 Characterization of Cr(VI) removal from aqueous solutions by a surplus agricultural waste-rice straw J. Hazard. Mater. 150 446 - 452    DOI : 10.1016/j.jhazmat.2007.04.126
Garg U.K. , Kaur M.P. , Garg V.K. , Suda D. 2007 Removal of hexavalent chromium from aqueous solution by agricultural waste biomass J. Hazard. Mater. 140 60 - 68    DOI : 10.1016/j.jhazmat.2006.06.056
Garg V.K. , Moirantthem A. , Rakesh K. , Renuka G. 2004 Basic dye (methylene blue) removal from simulated wastewater by adsorption using Indian rosewood sawdust: A timber industry waste Dyes Pigments. 63 243 - 250    DOI : 10.1016/j.dyepig.2004.03.005
Hanafiah M.A.K.M. , Ngah W.S.W. , Ibrahim S.C. , Zakaria H. , Ilias W.A.H.W. 2006 Kinetics and thermodynamic study of lead adsorption onto rubber (Hevea brasiliensis) leaf powder J. Appl. Sci. 6 2762 - 2767    DOI : 10.3923/jas.2006.2762.2767
Hashim M.A. , Chu K.H. 2004 Biosorption of cadmium by brown, green, and red seaweeds Chem. Eng. J. 97 249 - 255    DOI : 10.1016/S1385-8947(03)00216-X
Horsfall Jr. M. , Abia A.A. , Spiff A.I. 2006 Kinetic studies on the adsorption of Cd2+, Cu2+, and Zn2+ ions from aqueous solutions by cassava (Manihot sculenta Cranz) tuber bark waste Bioresour. Technol. 97 283 - 291    DOI : 10.1016/j.biortech.2005.02.016
Hossain M.A. , Ngo H.H. , Guo W.S. , Nguyen T.V. 2012 Removal of copper from water by adsorption onto banana peel as bioadsorbent Int. J. Geomate. 2 227 - 234
Kaewsarn P. , Saikaew W. , Wongcharee S. 2008 Dried biosorbent derived from banana peel: A potential biosorbent for removal of cadmium ions from aqueous solution Proceedings of the 18th Thailand Chemical Engineering and Applied Chemistry Conference Pattaya, Thailand October 20-21, 2008
Kamsonlian S. , Suresh S. , Balomajumder C. , Chand S. 2011 Biosorption of Cd(II) and As(III) ions from aqueous solution by tea waste biomass Afr. J. Environ. Sci. Technol. 5 1 - 7
Kamsonlian S. , Suresh S. , Majumder C.B. , Chand S. 2011 Characterization of banana and orange peels: Biosorption mechanism Int. J. Sci. Technol. Manag. 2 1 - 7
Karthikeyan S. , Balasubramanian R. , Iyer C.S.P. 2007 Evaluation of the marine algae Ulva fasciata and Sargassum sp. for the biosorption of Cu(II) from aqueous solutions Bioresour. Technol. 98 452 - 455    DOI : 10.1016/j.biortech.2006.01.010
King P. , Srivinas P. , Kumar Y.P , Prasad V.S.R.K. 2006 Sorption of copper(II) ion from aqueous solution by Tectona grandis l.f. (teak leaves powder) J. Hazard. Mater. B 136 560 - 566    DOI : 10.1016/j.jhazmat.2005.12.032
King P. , Anuradha K. , Lahari S.B. , Kumar Y.P. , Prasad V.S.R.K. 2007 Biosorption of zinc from aqueous solution using Azadirachta indica bark: equilibrium and kinetics studies J. Hazard. Mater. 152 324 - 329
Krishnani K.K. , Meng X. , Christodoulatos C. , Boddu V.M. 2008 Biosorption mechanism of nine different heavy metals onto biomatrix from rice husk J. Hazard. Mater. 153 1222 - 1234    DOI : 10.1016/j.jhazmat.2007.09.113
Kumar U. , Bandyopadhyay M. 2006 Fixed bed column study for Cd(II) removal from wastewater using treated rice husk J. Hazad. Mater. 129 253 - 259    DOI : 10.1016/j.jhazmat.2005.08.038
Lee S.M. , Davis A.P. 2001 Removal of Cu(II) and Cd(II) from aqueous solution by seafood processing waste sludge Water Res. 35 534 - 540    DOI : 10.1016/S0043-1354(00)00284-0
Leyva-Ramos R. , Bernal-Jacome L.A. , Acosta-Rodriguez I. 2005 Adsorption of cadmium(II) from aqueous solution on natural and oxidized corncob Sep. Purif. Technol. 45 41 - 49    DOI : 10.1016/j.seppur.2005.02.005
Li X. , Tang Y. , Cao X. , Lu D. , Luo F. , Shao W. 2008 Preparation and evaluation of orange peel cellulose adsorbents for effective removal of cadmium, zinc, cobalt, and nickel Coll. Surf. A 317 512 - 521    DOI : 10.1016/j.colsurfa.2007.11.031
Liu C. , Ngo H.H. , Guo W. , Tung K.L. 2012 Optimal conditions for preparation of banana peels, sugarcane bagasse and watermelon rind in removing copper from water Bioresour. Technol. 119 349 - 354    DOI : 10.1016/j.biortech.2012.06.004
Malkoc E. , Nuhoglu Y. 2007 Potential of tea factory waste for chromium (VI) removal from aqueous solutions: Thermodynamic and kinetic studies Sep. Purif. Technol. 54 291 - 298    DOI : 10.1016/j.seppur.2006.09.017
Memon J.R. , Memon S.Q. , Bhanger M.I. , Memon G.Z. , El-Turki A. , Allen G.C. 2008 Characterization of banana peel by scanning electron microscopy and FT-IR spectroscopy and its use for cadmium removal Colloids Surf. B 66 260 - 265    DOI : 10.1016/j.colsurfb.2008.07.001
Memon S.Q. , Bhanger M.I. , Khuhawar M.Y. 2005 Preconcentration and separation of Cr(III) and Cr(VI) using saw dust as a sorbent Anal. Bioanal. Chem. 383 619 - 624    DOI : 10.1007/s00216-005-3391-1
Memon S.Q. , Bhander M.I. , Memon J.R. 2008 Evaluation of banana peel for treatment of arsenic contaminated water Proceedings of the 1st Technical Meeting of Muslim Water Researchers Cooperation (MUWAREC) Malaysia December 2008 104 - 109
Miralles N. , Martinez M. , Florido A. , Casas I. , Fiol N. , Villaescusa I. 2008 Grape stalks waste as low cost biosorbents: An alternative for metal removal from aqueous solutions Solvent Extr. Ion Exc. 26 261 - 270    DOI : 10.1080/07366290802053660
Mohan D. , Pittman C.U. , Bricka M. , Smith F. , Yancey B. , Muhammad J. , Steele P.H. , Alexandre-Franco M.F. , Gomez-Serrano V. , Gong H. 2007 Sorption of arsenic, cadmium, and lead by chars produced from fast pyrolysis of wood and bark during bio-oil production J. Colloid Interface Sci. 310 57 - 73    DOI : 10.1016/j.jcis.2007.01.020
Mohapatra D. , Mishra S. , Sutar N. 2010 Banana and its by-product utilization; an overview J. Sci. Ind. Res. 69 323 - 329
Montanher S.F. , Oliveira E.A , Rollenberg M.C. 2005 Removal of metal ions from aqueous solutions by sorption onto rice bran J. Hazard. Mater. B 117 207 - 211    DOI : 10.1016/j.jhazmat.2004.09.015
Nasernejad B. , Zalah T.E. , Pou B.B. , Bygi M.E. , Zamani A. 2005 Comparison for biosorption modeling of heavy metals [Cr(III), Cu(II), Zn(II)] adsorption from wastewater by carrot residues Process Biochem. 40 1319 - 1322    DOI : 10.1016/j.procbio.2004.06.010
Noeline B.F. , Manohar D.M. , Anirudhan T.S. 2005 Kinetic and equilibrium modeling of lead(II) sorption from water and wastewater by polymerized banana stem in a batch reactor Sep. Purif. Technol. 45 131 - 140    DOI : 10.1016/j.seppur.2005.03.004
Opeolu B.O. , Fatoki O.S. 2012 Dynamics of zinc sorption from aqueous matrices using plantain (Musa sp.) peel biomass Afr. J. Biotechnol. 11 13194 - 13201
Ozer A. , O zer D. , O zer A. 2004 The adsorption of copper(II) ions onto dehydrated wheat bran (DWB): determination of equilibrium and thermodynamic parameters Process Biochem. 39 2183 - 2191    DOI : 10.1016/j.procbio.2003.11.008
Ozer A. , Pirincci H.B. 2006 The adsorption of Cd(II) ions on sulfuric acid-treated wheat bran J. Hazard. Mater. B 137 849 - 855    DOI : 10.1016/j.jhazmat.2006.03.009
Pagnanelli F. , Mainelli S. , Veglio F. , Toro L. 2003 Heavy metal removal by olive pomace: biosorbent characterization and equilibrium modeling Chem. Eng. Sci. 58 4709 - 4717    DOI : 10.1016/j.ces.2003.08.001
Park D. , Yun Y.S. , Park J.M. 2010 The past, present, and future trends of biosorption J. Biotechnol. Bioprocess Eng. 15 86 - 102    DOI : 10.1007/s12257-009-0199-4
Pehlivan E. , Altun T. , Parlayici S. 2009 Utilization of barley straws as biosorbents for Cu2+ and Pb2+ ions J. Hazard. Mater. 164 982 - 986    DOI : 10.1016/j.jhazmat.2008.08.115
Prasad A.G.D. , Abdulsalam M.A. 2009 Biosorption of Fe(II) from aqueous solution using tamarind bark and potato peel waste: equilibrium and kinetic studies J. App. Sc. In Environ. San. 4 273 - 282
Qi B.C. , Aldrich C. 2008 Biosorption of heavy metals from aqueous solutions with tobacco dust Bioresour. Technol. 99 5595 - 5601    DOI : 10.1016/j.biortech.2007.10.042
Reddad Z. , Gerente C. , Andres Y. , Le Cloirec P. 2002 Modeling of single and competitive metal adsorption onto a natural polysaccharide Environ. Sci. Technol. 36 2242 - 2248    DOI : 10.1021/es010237a
Reddad Z. , Gerente C. , Andres Y. , Ralet M.C. , Thibault J.F. , Cloirec P.L. 2002 Ni(II) and Cu(II) binding properties of native and modified sugar beet pulp Carbohydr. Polym. 49 23 - 31    DOI : 10.1016/S0144-8617(01)00301-0
Robinson T. , Chandran B. , Nigam P. 2002 Removal of dyes from a synthetic textile dye effluent by biosorption on apple pomace and wheat straw Water Res. 36 2824 - 2830    DOI : 10.1016/S0043-1354(01)00521-8
Sadon F.N. , Ibrahem A.S. , Ismail K.N. 2012 An overview of rice husk applications and modification techniques in wastewater treatment J. Purity, Utility React. Environ. 1 308 - 334
Saeed A. , Akhter M.W. , Iqbal M. 2005 Removal and recovery of heavy metals from aqueous solution using papaya wood as a new biosorbent Sep. Purif. Technol. 45 25 - 31    DOI : 10.1016/j.seppur.2005.02.004
Sawalha M.F. , Gardea-Torresdey J.L. , Parsons J.G. , Saupe G. , eralta-Vide J.R. 2005 Determination of adsorption and speciation of chromium species by saltbush (Atriplex canescens) biomass using a combination of XAS and ICP-OES Microchem. J. 81 122 - 132    DOI : 10.1016/j.microc.2005.01.008
Shafaghat A. , Salimi F. , Valiei M. , Salehzadeh J. , Shafaghat M. 2012 Removal of heavy metals (Pb2+,Cu2+, and r3+) from aqueous solutions using five plants materials Afr. J. Biotechnol. 11 852 - 855
Sheng P.X. , Ting Y. , Chen J.P. , Hong L. 2004 Sorption of lead, copper, cadmium, zinc, and nickel by marine algal biomass: characterization of biosorptive capacity and investigation of mechanisms J. Colloid Interface Sci. 275 131 - 141    DOI : 10.1016/j.jcis.2004.01.036
Shukla S.R. , Pai R.S. 2005 Adsorption of Cu(II), Ni(II), and Zn(II) on dye loaded groundnut shells and sawdust Sep. Purif. Technol. 43 1 - 8    DOI : 10.1016/j.seppur.2004.09.003
Shukla S.R. , Pai R.S. 2005 Adsorption of Cu(II), Ni(II), and Zn(II) on modified jute fibres Bioresour. Technol. 96 1430 - 1438    DOI : 10.1016/j.biortech.2004.12.010
Srivastava V.C. , Mall I.D. , Mishra I.M. 2006 Equilibrium modelling of single and binary adsorption of cadmium and nickel onto baggase fly ash J. Chem. Eng. 117 79 - 91    DOI : 10.1016/j.cej.2005.11.021
Sulak M.T. , Demirbas E. , Kobya M. 2006 Removal of Astrazon yellow 7GL from aqueous solutions by adsorption onto wheat bran Bioresour. Technol. 98 2590 - 2598
Verma A. , Chakraborty S. , Basu J.K. 2006 Adsorption study of hexavalent chromium using tamarind hull-based adsorbents Sep. Purif. Technol. 50 336 - 341    DOI : 10.1016/j.seppur.2005.12.007
Villaescusa I. , Fiol N. , Marti'nez M. , Miralles N. , Pocj J. , Serarols J. 2004 Removal of copper and nickel ions from aqueous solutions by grape stalks wastes Water Res. 38 992 - 1002    DOI : 10.1016/j.watres.2003.10.040
Volesky B. 2003 Sorption and Biosorption BV Sorbex Montreal, Canada
Wang X.S. , Qin Y. 2005 Equilibrium sorption isotherms of Cu2+ on rice bran Process Biochem. 40 677 - 680    DOI : 10.1016/j.procbio.2004.01.043
Xiaomin L. , Yanru T. , Zhexian X. , Yinghui L. , Fang L. 2007 Study on the preparation of orange peel cellulose adsorbents and biosorption of Cd2+rom aqueous solution Sep. Purif. Technol. 55 69 - 75    DOI : 10.1016/j.seppur.2006.10.025
Zafar M. N. , Nadeemb R. , Hanif M.A. 2007 Biosorption of nickel from protonated rice bran J. Hazard. Mater. 143 478 - 485    DOI : 10.1016/j.jhazmat.2006.09.055
Zhou M. , Liu Y. , Zeng G. , Li X. , Xu W. , Fan T. 2007 Kinetic and equilibrium studies of Cr(VI) biosorption by dead Bacillus licheniformis biomass World J. Microbiol. Biotechnol. 23 43 - 48    DOI : 10.1007/s11274-006-9191-8