A study on the potential applications of rice husk derivatives as useful adsorptive material
Mohammad Kashif Uddin, P. Fazul Rahaman
Rice husk is one of the by-products of rice production, left after the burning of rice husk. It can cause environmental pollution, as its disposal is difficult. Hence its proper reuse is necessary, and because it is mainly composed of carbon and silica, it could be used in adsorption processes for removal of toxic heavy metals from water and wastewaters. Rice husk is available in ample amount. Because of its high specific surface area, it has proven to be a potential low-cost material in the applications of water treatment and building materials. This literature reviews the properties, uses, and the importance of rice husk and provides an effective collection of studies to utilize rice husk derivatives. This economically valuable agriculture waste product is a great source of silica and has many comprehensive applications.
Rice Husk, Low Cost Material, Applications, Adsorption, Adsorption Capacity
Published online 8/1/2017, 38 pages
 M. K. Uddin, A review on the adsorption of heavy metals by clay minerals, with special focus on the past decade, Chem. Eng. J. 308 (2017) 438-462. https://doi.org/10.1016/j.cej.2016.09.029.
 M. Xu, P. Yin, X. Liu, Q. Tang, R. Qu, Q. Xu, Utilization of rice husks modified by organomultiphosphonic acids as low-cost biosorbents for enhanced adsorption of heavy metal ions, Bioresour. Technol. 149 (2013) 420–424. https://doi.org/10.1016/j.biortech.2013.09.075.
 M.A. Khan, M.K. Uddin, R. Bushra, A. Ahmad, S.A. Nabi, Synthesis and characterization of polyaniline Zr(IV) molybdophosphate for the adsorption of phenol from aqueous solution, React. Kinet. Mech. Catal. 113 (2014) 499-517. https://doi.org/10.1007/s11144-014-0751-x.
 R.A.K. Rao, M. Kashifuddin, Adsorption studies of Cd ( II ) on ball clay : Comparison with other natural clays, Arab. J. Chem. 9 (2016) S1233–S1241. https://doi.org/10.1016/j.arabjc.2012.01.010.
 M.G.Guiso, G.Alberti, G.Emma, M.Pesavento, Pb ( II ), Cu ( II ) and Cd ( II ) Removal through Untreated Rice Husk ; Thermodynamics and Kinetics, Anal. Sci, 28 (2012) 993-999.
 W.C. Li, F.Y. Law, Y.H.M. Chan, Biosorption studies on copper ( II ) and cadmium ( II ) using pretreated rice straw and rice husk, 24 (2017)8903–8915. https://doi.org/10.1007/s11356-015-5081-7.
 R.A.K. Rao, M. Kashifuddin, Pottery glaze―An excellent adsorbent for the removal of Cu(II) from aqueous solution, Chin.J.Geochem. 31 (2012) 136–146. https://doi.org/10.1007/s11631-012-0560-8.
 R.A.K. Rao, F. Rehman, M. Kashifuddin, Removal of Cr(VI) from electroplating wastewater using fruit peel of Leechi (Litchi chinensis) Desal. Water Treat.49 (2012) 136-146. https://doi.org/10.1080/19443994.2012.708211.
 D. Augusto, M. Zaia, R. Ventura, A. Alberto, Use of rice straw as biosorbent for removal of Cu ( II ), Zn ( II ), Cd ( II ) and Hg ( II ) ions in industrial effluents, J. Hazard. Mater. 166 (2009) 383–388. https://doi.org/10.1016/j.jhazmat.2008.11.074.
 T. Kumar, A. Kumar, S. Mandal, S. Kumar, The sorption of lead ( II ) ions on rice husk ash, J. Hazard. Mater. 163 (2009) 1254–1264. https://doi.org/10.1016/j.jhazmat.2008.07.119.
 C. Jeon, Removal of copper ion using rice hulls, J. Ind. Eng. Chem. 17 (2011) 517–520. https://doi.org/10.1016/j.jiec.2010.10.020.
 Z. Elouear, F. Bouhamed, N. Boujelben, J. Bouzid, Application of sheep manure and potassium fertilizer to contaminated soil and its effect on zinc , cadmium and lead accumulation by alfalfa plants, Sustain. Environ. Res. (2016) 5–9. https://doi.org/10.1016/j.serj.2016.04.004.
 R.M. Ali, H.A. Hamad, M.M. Hussein, G.F. Malash, Potential of using green adsorbent of heavy metal removal from aqueous solutions : Adsorption kinetics , isotherm , thermodynamic , mechanism and economic analysis, Ecol. Engg. 91 (2016) 317–332.
 R.A.K. Rao, M. Kashifuddin, Adsorption Properties of Coriander Seed Powder (Coriandrum sativum): Extraction and Pre-concentration of Pb(II), Cu(II) and Zn(II) Ions from Aqueous Solution, Adsorpt. Sci. Technol. 30 (2012) 127-146.
 R. A.K. Rao, S. Ikram, M.K. Uddin, Removal of Cr(VI) from aqueous solution on seeds of Artimisia absinthium (novel plant material) Desalin. Water Treat. 54 (2015) 3358–3371. https://doi.org/10.1080/19443994.2014.908147.
 R.A.K. Rao, S. Ikram, M.K. Uddin, Removal of Cd(II) from aqueous solution by exploring the biosorption characteristics of gaozaban (Onosma bracteatum)J. Environ. Chem. Eng. 2 (2014) 1155–1164.
 R. Lavecchia, F. Medici, M.S. Patterer, A. Zuorro, Lead Removal from Water by Adsorption on Spent Coffee Grounds, 47 (2016) 295–300. https://doi.org/10.3303/CET1647050.
 S. Asgarzadeh, R. Rostamian, E. Faez, A. Maleki, Biosorption of Pb ( II ), Cu ( II ), and Ni ( II ) ions onto novel lowcost Peldarica leaves-based biosorbent : isotherm , kinetics , and operational parameters investigation, 57 (2016)14544-14551. https://doi.org/10.1080/19443994.2015.1067831.
 A.K. Bhattacharya, T.K. Naiya, S.N. Mandal, S.K. Das, Adsorption, kinetics and equilibrium studies on removal of Cr(VI) from aqueous solutions using different low-cost adsorbents, Chem. Eng. J. 137 (2008) 529–541. https://doi.org/10.1016/j.cej.2007.05.021.
 A. Witek-krowiak, R.G. Szafran, S. Modelski, Biosorption of heavy metals from aqueous solutions onto peanut shell as a low-cost biosorbent, Desal.. 265 (2011) 126–134. https://doi.org/10.1016/j.desal.2010.07.042.
 X. Jing, Y. Cao, X. Zhang, D. Wang, X. Wu, H. Xu, Biosorption of Cr ( VI ) from simulated wastewater using a cationic surfactant modi fi ed spent mushroom, Desal.. 269 (2011) 120–127. https://doi.org/10.1016/j.desal.2010.10.050.
 C. Chung, Y. Shen, Y. Min, M. Kuang, C. San, C. Yi, Y. An, Biosorption of chromium , copper and zinc on rice wine processing waste sludge in fixed bed, Desal. 267 (2011) 20–24. https://doi.org/10.1016/j.desal.2010.08.040.
 A.H. El-sheikh, M.M.A. Hilal, J.A. Sweileh, Bioresource Technology Bio-separation , speciation and determination of chromium in water using partially pyrolyzed olive pomace sorbent, Bioresour. Technol. 102 (2011) 5749–5756. https://doi.org/10.1016/j.biortech.2011.03.021.
 A.D. Papandreou, C.J. Stournaras, D. Panias, I. Paspaliaris, Adsorption of Pb ( II ), Zn ( II ) and Cr ( III ) on coal fly ash porous pellets, Miner. Eng. 24 (2011) 1495–1501. https://doi.org/10.1016/j.mineng.2011.07.016.
 S. Chen, Q. Yue, B. Gao, Q. Li, X. Xu, K. Fu, Adsorption of hexavalent chromium from aqueous solution by modified corn stalk : A fixed-bed column study, Bioresour. Technol. (2011). https://doi.org/10.1016/j.biortech.2011.11.110.
 S. Liang, N. Ye, Y. Hu, Y. Shi, W. Zhang, W. Yu, X. Wu, Lead adsorption from aqueous solutions by a granular adsorbent prepared from phoenix tree, RSC Adv. 10 (2016) 25393–25400. https://doi.org/10.1039/C6RA03258C.
 Z.N. Garba, I. Bello, A. Galadima, A.Y. Lawal, Optimization of adsorption conditions using central composite design for the removal of copper ( II ) and lead ( II ) by defatted papaya seed, Karbala Int. J. Mod. Sci. 2 (2016) 20–28. https://doi.org/10.1016/j.kijoms.2015.12.002.
 C. Duran, D. Ozdes, A. Gundogdu, M. Imamoglu, H. Basri, Tea-industry waste activated carbon , as a novel adsorbent , for separation , preconcentration and speciation of chromium, Anal. Chim. Acta. 688 (2011) 75–83. https://doi.org/10.1016/j.aca.2010.12.029.
 T.S.Anurandhan, .P.G. Radhakrishnan, Thermodynamics of chromium ( III ) adsorption onto a cation exchanger derived from saw dust of Jack wood, Env. Chem. Lett. (2011) 121–125. https://doi.org/10.1007/s10311-009-0255-5.
 A. Sdiri, T. Higashi, F. Jamoussi, S. Bouaziz, Effects of impurities on the removal of heavy metals by natural limestones in aqueous systems, J. Environ. Manage. 93 (2012) 245–253. https://doi.org/10.1016/j.jenvman.2011.08.002.
 Y. Shen, S. Wang, Y. Tzou, Y. Yan, W. Kuan, Removal of hexavalent Cr by coconut coir and derived chars – The effect of surface functionality, Bioresour. Technol. 104 (2012) 165–172. https://doi.org/10.1016/j.biortech.2011.10.096.
 A. Javaid, R. Bajwa, U. Shafique, J. Anwar, Removal of heavy metals by adsorption on Pleurotus ostreatus, Biomass and Bioenergy. 35 (2011) 1675–1682. https://doi.org/10.1016/j.biombioe.2010.12.035.
 T. Altun, E. Pehlivan, Removal of Cr ( VI ) from aqueous solutions by modified walnut shells, Food Chem. 132 (2012) 693–700. https://doi.org/10.1016/j.foodchem.2011.10.099.
 R.M. Lattuada, M.C.R. Peralba, J.H.Z. Dos Santos, A.G. Fisch, Peat , Rice Husk and Rice Husk Carbon as Low- Cost Adsorbents for Metals from Acidic Aqueous Solutions, Sep. Sci. Tech. 49 (2014) 101- 111. https://doi.org/10.1080/01496395.2013.815476.
 S. Noor Syuhadah, H. Rohasliney, Rice Husk as biosorbent: A Review, Heal. Environ. J. 3 (2012) 89–95.
 L. Armesto, A. Bahillo, K. Veijonen, A. Cabanillas, J. Otero, Combustion behaviour of rice husk in a bubbling fluidised bed, Biomass Bioenergy. 23 (2002) 171–179.
 E.I. El-Shafey, Behaviour of Reduction–Sorption of Chromium (VI) from an Aqueous Solution on a Modified Sorbent from Rice Husk, Water, Air, Soil Poll. 163 (2005) 81–102.
 K. Kenes, O. Yerdos, M. Zulkhair, D. Yerlan, Study on the effectiveness of thermally treated rice husks for petroleum adsorption, J. Non. Cryst. Solids. 358 (2012) 2964–2969. https://doi.org/10.1016/j.jnoncrysol.2012.07.017.
 D.S. Jung, M.-H. Ryou, Y.J. Sung, S. Bin Park, J.W. Choi, Recycling rice husks for high-capacity lithium battery anodes., Proc. Natl. Acad. Sci. U. S. A. 110 (2013) 12229–34. https://doi.org/10.1073/pnas.1305025110.
 T.H. Liou, C.C. Yang, Synthesis and surface characteristics of nanosilica produced from alkali-extracted rice husk ash, Mater. Sci. Eng. B 176 (2011) 521–529. https://doi.org/10.1016/j.mseb.2011.01.007.
 V. Della, I. Kuhn, D. Hotza, Rice husk ash as an elemente source for active silicaproduction, Mater. Lett. 57 (2002) 818–821. https://doi.org/10.1016/S0167-577X(02)00879-0.
 R. V Krishnarao, M.M. Godkhindi, Distribution of Silica in Rice Husks and its effect on the Formation of Silicon Carbide, Ceram. Int. 18 (1992) 243–249. https://doi.org/10.1016/0272-8842(92)90102-J.
 H. Muramatsu, Y.A. Kim, K.S. Yang, R. Cruz-Silva, I. Toda, T. Yamada, M. Terrones, M. Endo, T. Hayashi, H. Saitoh, Rice husk-derived graphene with nano-sized domains and clean edges, Small. 10 (2014) 2766–2770. https://doi.org/10.1002/smll.201400017.
 S. Sankar, S.K. Sharma, N. Kaur, B. Lee, D.Y. Kim, S. Lee, H. Jung, Biogenerated silica nanoparticles synthesized from sticky, red, and brown rice husk ashes by a chemical method, Ceram. Int. 42 (2016) 4875–4885. https://doi.org/10.1016/j.ceramint.2015.11.172.
 N. Yalçin, V. Sevinç, Studies on silica obtained from rice husk, Ceram. Int. 27 (2001) 219–224. https://doi.org/10.1016/S0272-8842(00)00068-7.
 S. Apoorv, R. Khalid, Physical and Chemical Properties of Rice Husk Ash and Ground Granulated Blast Furnace Slag- A Review, Glob. J. Eng. Sci. Res. 1 (2014).
 A.N. Givi, S.A. Rashid, F.N.A. Aziz, M.A.M. Salleh, Assessment of the effects of rice husk ash particle size on strength, water permeability and workability of binary blended concrete, Constr. Build. Mater. 24 (2010) 2145–2150. https://doi.org/10.1016/j.conbuildmat.2010.04.045.
 Q. Feng, H. Yamamichi, M. Shoya, S. Sugita, Study on the pozzolanic properties of rice husk ash by hydrochloric acid pretreatment, Cem. Concr. Res. 34 (2004) 521–526. https://doi.org/10.1016/j.cemconres.2003.09.005.
 M. Nehdi, J. Duquette, A. El Damatty, Performance of rice husk ash produced using a new technology as a mineral admixture in concrete, Cem. Concr. Res. 33 (2003) 1203–1210. https://doi.org/10.1016/S0008-8846(03)00038-3.
 W. Xu, T.Y. Lo, S.A. Memon, Microstructure and reactivity of rich husk ash, Constr. Build. Mater. 29 (2012) 541–547. https://doi.org/10.1016/j.conbuildmat.2011.11.005.
 D.D. Bui, J. Hu, P. Stroeven, Particle size effect on the strength of rice husk ash blended gap-graded Portland cement concrete, Cem. Concr. Compos. 27 (2005) 357–366. https://doi.org/10.1016/j.cemconcomp.2004.05.002.
 M.H. Zhang, R. Lastra, V.M. Malhotra, Rice-husk ash paste and concrete: Some aspects of hydration and the microstructure of the interfacial zone between the aggregate and paste, Cem. Concr. Res. 26 (1996) 963–977. https://doi.org/10.1016/0008-8846(96)00061-0.
 M. Reddy, D.V., Alvarez, Marine Durability Characteristics of Rice Husk Ash-Modified Reinforced Concrete, in: Fourth LACCEI Int. Lat. Am. Caribb. Conf. Eng. Technol., Mayagüez, Puerto Rico, 2006.
 G.R. Rao, A.R.K. Sastry, P.K. Rohatgi, Nature and reactivity of silica available in rice husk and its ashes, Bull. Mater. Sci. 12 (1989) 469–479. https://doi.org/10.1007/BF02744917.
 V.T.A. Van, C. Rößler, D.D. Bui, H.M. Ludwig, Rice husk ash as both pozzolanic admixture and internal curing agent in ultra-high performance concrete, Cem. Concr. Compos. 53 (2014) 270–278. https://doi.org/10.1016/j.cemconcomp.2014.07.015.
 A.L.G. Gastaldini, G.C. Isaia, A.P. Saciloto, F. Missau, T.F. Hoppe, Influence of curing time on the chloride penetration resistance of concrete containing rice husk ash: A technical and economical feasibility study, Cem. Concr. Compos. 32 (2010) 783–793. https://doi.org/10.1016/j.cemconcomp.2010.08.001.
 P.M. Yeletsky, V.A. Yakovlev, M.S. Mel’gunov, V.N. Parmon, Synthesis of mesoporous carbons by leaching out natural silica templates of rice husk, Microporous Mesoporous Mater. 121 (2009) 34–40. https://doi.org/10.1016/j.micromeso.2008.12.025.
 U.R. Lakshmi, V.C. Srivastava, I.D. Mall, D.H. Lataye, Rice husk ash as an effective adsorbent: Evaluation of adsorptive characteristics for Indigo Carmine dye, J. Environ. Manage. 90 (2009) 710–720. https://doi.org/10.1016/j.jenvman.2008.01.002.
 M. Jamil, M.N.N. Khan, M.R. Karim, A.B.M.A. Kaish, M.F.M. Zain, Physical and chemical contributions of Rice Husk Ash on the properties of mortar, Constr. Build. Mater. 128 (2016) 185–198. https://doi.org/10.1016/j.conbuildmat.2016.10.029.
 Q. Feng, Q. Lin, F. Gong, S. Sugita, M. Shoya, Adsorption of lead and mercury by rice husk ash, J. Colloid Interface Sci. 278 (2004) 1–8. https://doi.org/10.1016/j.jcis.2004.05.030.
 K.Y. Foo, B.H. Hameed, Utilization of rice husk ash as novel adsorbent: A judicious recycling of the colloidal agricultural waste, Adv. Colloid Interface Sci. 152 (2009) 39–47. https://doi.org/10.1016/j.cis.2009.09.005.
 R. V Krishnarao, J. Subrahmanyam, T.J. Kumar, Studies on the Formation of Black Particles in Rice Husk Silcia Ash, J. Eur. Ceram. Soc. 21 (2001) 99–104.
 X. Liu, X. Chen, L. Yang, H. Chen, Y. Tian, Z. Wang, A review on recent advances in the comprehensive application of rice husk ash, Res. Chem. Intermed. 42 (2016) 893–913. https://doi.org/10.1007/s11164-015-2061-y.
 K. Xu, Q. Sun, Y. Guo, Y. Zhang, S. Dong, Preparation of super-hydrophobic white carbon black from nano-rice husk ash, Res. Chem. Intermed. 40 (2014) 1965–1973. https://doi.org/10.1007/s11164-013-1094-3.
 P. Chindaprasirt, S. Rukzon, V. Sirivivatnanon, Resistance to chloride penetration of blended Portland cement mortar containing palm oil fuel ash, rice husk ash and fly ash, Constr. Build. Mater. 22 (2008) 932–938. https://doi.org/10.1016/j.conbuildmat.2006.12.001.
 W. Tangchirapat, R. Buranasing, C. Jaturapitakkul, P. Chindaprasirt, Influence of rice husk-bark ash on mechanical properties of concrete containing high amount of recycled aggregates, Constr. Build. Mater. 22 (2008) 1812–1819. https://doi.org/10.1016/j.conbuildmat.2007.05.004.
 A.L.G. Gastaldini, G.C. Isaia, T.F. Hoppe, F. Missau, A.P. Saciloto, Influence of the use of rice husk ash on the electrical resistivity of concrete: A technical and economic feasibility study, Constr. Build. Mater. 23 (2009) 3411–3419. https://doi.org/10.1016/j.conbuildmat.2009.06.039.
 M.R. Karim, M.F.M. Zain, M. Jamil, F.C. Lai, M.N. Islam, Use of wastes in construction industries as an energy saving approach, Energy Procedia. 12 (2011) 915–919. https://doi.org/10.1016/j.egypro.2011.10.120.
 A. Nazari, Predicting the total specific pore volume of geopolymers produced from waste ashes by gene expression programming, Neural Comput. Appl. 15 (2012) 1–7. https://doi.org/10.1007/s00521-012-1135-7.
 U.. Hassan, M.. Maharaz, The effects of Rice Husk Ash on Porcelain composition, Sci. World J. 10 (2015) 7–16.
 B.M. Miyandehi, A. Feizbakhsh, M.A. Yazdi, Q. feng Liu, J. Yang, P. Alipour, Performance and properties of mortar mixed with nano-CuO and rice husk ash, Cem. Concr. Compos. 74 (2016) 225–235. https://doi.org/10.1016/j.cemconcomp.2016.10.006.
 S.M.S. Kazmi, S. Abbas, M.A. Saleem, M.J. Munir, A. Khitab, Manufacturing of sustainable clay bricks: Utilization of waste sugarcane bagasse and rice husk ashes, Constr. Build. Mater. 120 (2016) 29–41. https://doi.org/10.1016/j.conbuildmat.2016.05.084.
 R. Siddique, K. Singh, Kunal, M. Singh, V. Corinaldesi, A. Rajor, Properties of bacterial rice husk ash concrete, Constr. Build. Mater. 121 (2016) 112–119. https://doi.org/10.1016/j.conbuildmat.2016.05.146.
 W. Yang, Y. Xue, S. Wu, Y. Xiao, M. Zhou, Performance investigation and environmental application of basic oxygen furnace slag ??? Rice husk ash based composite cementitious materials, Constr. Build. Mater. 123 (2016) 493–500. https://doi.org/10.1016/j.conbuildmat.2016.07.051.
 P. Sturm, G.J.G. Gluth, H.J.H. Brouwers, H.C. Kühne, Synthesizing one-part geopolymers from rice husk ash, Constr. Build. Mater. 124 (2016) 961–966. https://doi.org/10.1016/j.conbuildmat.2016.08.017.
 A. Mohammad, Inamuddin, S. Hussain, Poly (3,4-ethylenedioxythiophene): polystyrene sulfonate (PEDOT:PSS) Zr(IV) phosphate composite cation exchanger : sol-gel synthesis and physicochemical characterization, Ionics (Kiel). 21 (2015) 1063–1071.
 J. Alex, J. Dhanalakshmi, B. Ambedkar, Experimental investigation on rice husk ash as cement replacement on concrete production, Constr. Build. Mater. 127 (2016) 353–362. https://doi.org/10.1016/j.conbuildmat.2016.09.150.
 Inamuddin, Y.A. Ismail, Synthesis and characterization of electrically conducting poly-o-methoxyaniline Zr(1V) molybdate Cd(II) selective composite cation-exchanger, Desalination. 250 (2010) 523–529.
 D.T. Ambas, G. Mikhael, C. Dela Rosa, L.J.A. Esquejo, J.D. Gil, M.L. Magtalas, C.J.D. Rubinas, Effect of Rice Husk Ash as Cement Replacement in the Compressive Strength of Hydraulic Cement Mortar Cube, IEEE Explor (2015) 8–10.
 A.A. Ramezanianpour, M. Mahdikhani, Gh. Ahmadibeni, The effect of rice husk ash on mechanical properties and durability of sustainabe concretes, Int. J. Civ. Eng. 7 (2009) 83–91.
 K. Mohanta, D. Kumar, O. Parkash, Properties and Industrial Applications of Rice husk : A review, Int. J. Emerg. Technol. Adv. Eng. 2 (2012) 86–90.
 N. Priyantha, A.N. Navaratne, T. Kulasooriya, Adsorption of Heavy Metal Ions on Rice Husk : Isotherm Modeling and Error Analysis, Int. J. Earth Sci. Eng. 8 (2015) 346–352.
 A.S.M. E.A. Basha , R. Hashim , H.B. Mahmud, Stabilization of residual soil with rice husk ash and cement, J. Tek. Sipil. 5 (2004) 1–84.
 J.M. Dias, M.C.M. Alvim-Ferraz, M.F. Almeida, J. Rivera-Utrilla, M. Sánchez-Polo, Waste materials for activated carbon preparation and its use in aqueous-phase treatment: A review, J. Environ. Manage. 85 (2007) 833–846. https://doi.org/10.1016/j.jenvman.2007.07.031.
 O. Ioannidou, A. Zabaniotou, Agricultural residues as precursors for activated carbon production-A review, Renew. Sustain. Energy Rev. 11 (2007) 1966–2005. https://doi.org/10.1016/j.rser.2006.03.013.
 W.S. Wan-Ngah, M.A.K.M. Hanafiah, Removal of heavy metal ions from wastewater by chemically modified plant wastes as adsorbents: A review, Bioresour. Technol. 99 (2008) 3935–3948. https://doi.org/10.1016/j.biortech.2007.06.011.
 W.C. Li, F.Y. Law, Y.H.M. Chan, Biosorption studies on copper (II) and cadmium (II) using pretreated rice straw and rice husk, Environ. Sci. Pollut. Res. (2015) 1–3. https://doi.org/10.1007/s11356-015-5081-7.
 D. Angelova, I. Uzunov, S. Uzunova, A. Gigova, L. Minchev, Kinetics of oil and oil products adsorption by carbonized rice husks, Chem. Eng. J. 172 (2011) 306–311. https://doi.org/10.1016/j.cej.2011.05.114.
 P. Vassileva, A. Detcheva, I. Uzunov, S. Uzunova, Removal of Metal Ions From Aqueous Solutions Using Pyrolyzed Rice Husks: Adsorption Kinetics and Equilibria, Chem. Eng. Commun. 200 (2013) 1578–1599. https://doi.org/10.1080/00986445.2012.755519.
 Y. Zhang, J. Zhao, Z. Jiang, D. Shan, Y. Lu, Biosorption of Fe (II) and Mn (II) Ions from Aqueous Solution by Rice Husk Ash, Biomed Res. Int. 2014 (2014) 1–10.
 Santi, I. Raya, M. Zakir, The Adsorption of Pb ( II ) Ions on Activated Carbon from Rice Husk , Irradiated by Ultrasonic Waves : Kinetic and Thermodynamics Studies, J. Nat. Sci. Res. 4 (2014) 18–24.
 A. Elham, T. Hossein, H. Mahnoosh, Removal of Zn(II) and Pb (II) ions Using Rice Husk in Food Industrial Wastewater, J. Appl. Sci. Environ. Manag. 14 (2010) 159–162. https://doi.org/http://dx.doi.org/10.4314/jasem.v14i4.63306.
 S. Sugashini, K.M.M.S. Begum, Adsorption and desorption studies on the performance of Fe-loaded chitosan carbonized rice husk for metal ion removal, Desalin. Water Treat. 51 (2013) 7764–7774. https://doi.org/10.1080/19443994.2013.793947.
 M.G.A. Vieira, A.F.D.A. Neto, M.G.C. da-Silva, C.N. Carneiro, A.A.M. Filho, Adsorption of Lead and Copper Ions From Aqueous Effluents on Rice Husk Ash in a Dynamic System, Brazilian J. Chem. Eng. 31 (2014) 519–529. https://doi.org/10.1590/0104-6632.20140312s00002103.
 A.M. Youssef, A.I. Ahmed, M.I. Amin, U.A. El-Banna, Adsorption of lead by activated carbon developed from rice husk, Desalin. Water Treat. 54 (2014) 1–14. https://doi.org/10.1080/19443994.2014.896289.
 A.I. Habib, S.R.M. Kutty, N. Shafiq, M.F. Nuruddin, Adsorption of Metals (Zn, Ca and B) in Used Engine Oil by Using Microwave Incinerated Rice Husk Ash (MIRHA), in: InCIEC (2014) 1065-1073. https://link.springer.com/chapter/10.1007/978-981-287-290-6_94.
 D. Sarkar, S.K. Das, A. Bandyopadhyay, Analysis of Bio-Sorption of Cr(VI) onto Raw Rice Husk by a Hybrid Theoretical Model Using Results of Batch Experiments, Adsorpt. Sci. Technol. 31 (2013) 747–766. https://doi.org/10.1260/0263-6188.8.131.527.
 F.A. Adekola, D.S.S. Hodonou, H.I. Adegoke, Thermodynamic and kinetic studies of biosorption of iron and manganese from aqueous medium using rice husk ash, Appl. Water Sci. 6 (2016) 319–330.
 S. Sugashini, K.M.M.S. Begum, Studies on the Performance of Ethylamine- Modified Chitosan Carbonized Rice Husk Composite Beads for Adsorption of Metal Ion, Bioremediat. J. 17 (2013) 97–106. https://doi.org/http://dx.doi.org/10.1080/10889868.2013.786016.
 Y. Ding, D. Jing, H. Gong, L. Zhou, X. Yang, Biosorption of aquatic cadmium(II) by unmodified rice straw, Bioresour. Technol. 114 (2012) 20–25. https://doi.org/10.1016/j.biortech.2012.01.110.
 N.A. Sari, C.F. Ishak, R.A. Bakar, Characterization of oil palm empty fruit bunch and rice husk biochars and their potential to adsorb arsenic and cadmium, Am. J. Agric. Biol. Sci. 9 (2014) 450–456. https://doi.org/10.3844/ajabssp.2014.450.456.
 A. Masoumi, K. Hemmati, M. Ghaemy, Low-cost nanoparticles sorbent from modified rice husk and a copolymer for efficient removal of Pb(II) and crystal violet from water, Chemosphere. 146 (2016) 253–262. https://doi.org/10.1016/j.chemosphere.2015.12.017.
 S.T. Song, N. Saman, K. Johari, H. Mat, Surface chemistry modifications of rice husk toward enhancement of Hg(II) adsorption from aqueous solution, Clean Technol. Environ. Policy. 16 (2014) 1747–1755. https://doi.org/10.1007/s10098-014-0803-y.
 N. Li, J. Zhao, Z. Jiang, B. Cao, Y. Lu, D. Shan, Y. Zhang, Continuous manganese(II) ions removal from aqueous solutions using rice husk ash-packed column reactor, Desalin. Water Treat. 3994 (2016) 1–9. https://doi.org/10.1080/19443994.2015.1128362.
 S. Sarkar, S.K. Das, Removal of Cr(VI) and Cu(II) ions from aqueous solution by rice husk ash—column studies, Desalin. Water Treat. 57 (2016) 20340–20349. https://doi.org/10.1080/19443994.2015.1107754.
 S. Sobhanardakani, H. Parvizimosaed, E. Olyaie, Heavy metals removal from wastewaters using organic solid waste-rice husk, Environ. Sci. Pollut. Res. 20 (2013) 5265–5271. https://doi.org/10.1007/s11356-013-1516-1.
 L.S. Rocha, I. Lopes, C.B. Lopes, B. Henriques, A.M.V.M. Soares, A.C. Duarte, E. Pereira, Efficiency of a cleanup technology to remove mercury from natural waters by means of rice husk biowaste: Ecotoxicological and chemical approach, Environ. Sci. Pollut. Res. 21 (2014) 8146–8156. https://doi.org/10.1007/s11356-014-2753-7.
 N.A. Sánchez-Flores, M. Solache, M.T. Olguín, J.J. Fripiat, G. Pacheco-Malagón, J.M. Saniger, S. Bulbulian, Selectivity of the Cd2+/Ca2+ exchange on modified rice hull silica, Environ. Technol. 30 (2009) 269–275. https://doi.org/10.1080/09593330802573290.
 T.K. Naiya, B. Singha, S.K. Das, FTIR Study for the Cr ( VI ) Removal from Aqueous Solution Using Rice Waste, Int. Proc. Chem. Biol. Environ. Eng. 10 (2011) 114–119.
 S. Kamsonlian, S. Suresh, V. Ramanaiah, C.B. Majumder, S. Chand, A. Kumar, Biosorptive behaviour of mango leaf powder and rice husk for arsenic(III) from aqueous solutions, Int. J. Environ. Sci. Technol. 9 (2012) 565–578. https://doi.org/10.1007/s13762-012-0054-6.
 A.W. Samsuri, F. Sadegh-Zadeh, B.J. Seh-Bardan, Characterization of biochars produced from oil palm and rice husks and their adsorption capacities for heavy metals, Int. J. Environ. Sci. Technol. 11 (2014) 967–976. https://doi.org/10.1007/s13762-013-0291-3.
 S. Luo, M.N. Shen, F. Wang, Q.R. Zeng, J.H. Shao, J.D. Gu, Synthesis of Fe3O4-loaded porous carbons developed from rice husk for removal of arsenate from aqueous solution, Int. J. Environ. Sci. Technol. 13 (2016) 1137–1148. https://doi.org/10.1007/s13762-016-0955-x.
 S. Aktas, M.H. Morcali, Gold uptake from dilute chloride solutions by a Lewatit TP 214 and activated rice husk, Int. J. Miner. Process. 101 (2011) 63–70. https://doi.org/10.1016/j.minpro.2011.07.007.
 O.J. Achadu, O.O. Ayejuyo, F.E. Ako, C.L. Dalla, O.O. Olaoye, Synchronous Adsorption of Cadmium and Lead ions from Aqueous Media by Rice Husk Ash and Sodium Dodecyl Sulfate Combination, Int. J. Mod. Anal. Sep. Sci. 3 (2014) 20–39.
 P. Taylor, G.C. Pathiraja, D.K. De Silva, L. Dhanapala, Desalination and Water Treatment Investigating the surface characteristics of chemically modified and unmodified rice husk ash ; bottom- up approach for adsorptive removal of water contaminants, Desalin. Water Treat. 3994 (2015) 37–41. https://doi.org/10.1080/19443994.2014.883133.
 A.G. El-Said, N.A. Badawy, A.Y. Abdel-Aal, S.E. Garamon, Optimization parameters for adsorption and desorption of Zn(II) and Se(IV) using rice husk ash: Kinetics and equilibrium, Ionics. 17 (2011) 263–270. https://doi.org/10.1007/s11581-010-0505-3.
 L. Vlaev, S. Turmanova, A. Dimitrova, Kinetics and thermodynamics of water adsorption onto rice husks ash filled polypropene composites during soaking, J. Polym. Res. 16 (2009) 151–164. https://doi.org/10.1007/s10965-008-9213-3.
 C. Jeon, Removal of copper ion using rice hulls, J. Ind. Eng. Chem. 17 (2011) 517–520. https://doi.org/10.1016/j.jiec.2010.10.020.
 H. Aydin, Y. Bulut, Ç. Yerlikaya, Removal of copper (II) from aqueous solution by adsorption onto low-cost adsorbents, J. Environ. Manage. 87 (2008) 37–45. https://doi.org/10.1016/j.jenvman.2007.01.005.
 S.A. Abo-El-Enein, M.A. Eissa, A.A. Diafullah, M.A. Rizk, F.M. Mohamed, Removal of some heavy metals ions from wastewater by copolymer of iron and aluminum impregnated with active silica derived from rice husk ash, J. Hazard. Mater. 172 (2009) 574–579. https://doi.org/10.1016/j.jhazmat.2009.07.036.
 T.K. Naiya, A.K. Bhattacharya, S. Mandal, S.K. Das, The sorption of lead(II) ions on rice husk ash, J. Hazard. Mater. 163 (2009) 1254–1264. https://doi.org/10.1016/j.jhazmat.2008.07.119.
 C.G. Rocha, D.A.M. Zaia, R.V. da S. Alfaya, A.A. da S. Alfaya, Use of rice straw as biosorbent for removal of Cu(II), Zn(II), Cd(II) and Hg(II) ions in industrial effluents, J. Hazard. Mater. 166 (2009) 383–388. https://doi.org/10.1016/j.jhazmat.2008.11.074.
 N. Sharma, K. Kaur, S. Kaur, Kinetic and equilibrium studies on the removal of Cd2+ ions from water using polyacrylamide grafted rice (Oryza sativa) husk and (Tectona grandis) saw dust, J. Hazard. Mater. 163 (2009) 1338–1344. https://doi.org/10.1016/j.jhazmat.2008.07.135.
 M. Bansal, U. Garg, D. Singh, V.K. Garg, Removal of Cr(VI) from aqueous solutions using pre-consumer processing agricultural waste: A case study of rice husk, J. Hazard. Mater. 162 (2009) 312–320. https://doi.org/10.1016/j.jhazmat.2008.05.037.
 X. Luo, Z. Deng, X. Lin, C. Zhang, Fixed-bed column study for Cu2+ removal from solution using expanding rice husk, J. Hazard. Mater. 187 (2011) 182–189. https://doi.org/10.1016/j.jhazmat.2011.01.019.
 K.K. Krishnani, X. Meng, C. Christodoulatos, V.M. Boddu, Biosorption mechanism of nine different heavy metals onto biomatrix from rice husk, J. Hazard. Mater. 153 (2008) 1222–1234. https://doi.org/10.1016/j.jhazmat.2007.09.113.
 S. Mohan, G. Sreelakshmi, Fixed bed column study for heavy metal removal using phosphate treated rice husk, J. Hazard. Mater. 153 (2008) 75–82. https://doi.org/10.1016/j.jhazmat.2007.08.021.
 V.G. Georgieva, M.P. Tavlieva, S.D. Genieva, L.T. Vlaev, Adsorption kinetics of Cr(VI) ions from aqueous solutions onto black rice husk ash, J. Mol. Liq. 208 (2015) 219–226. https://doi.org/10.1016/j.molliq.2015.04.047.
 M.P. Tavlieva, S.D. Genieva, V.G. Georgieva, L.T. Vlaev, Thermodynamics and kinetics of the removal of manganese(II) ions from aqueous solutions by white rice husk ash, J. Mol. Liq. 211 (2015) 938–947. https://doi.org/10.1016/j.molliq.2015.08.015.
 M.S. Lashkenari, B. Davodi, H. Eisazadeh, Removal of arsenic from aqueous solution using polyaniline/rice husk nanocomposite, Korean J. Chem. Eng. 28 (2011) 1532–1538. https://doi.org/10.1007/s11814-011-0014-8.
 Y. Fan, R. Yang, Z. Lei, N. Liu, J. Lv, S. Zhai, B. Zhai, L. Wang, Removal of Cr(VI) from aqueous solution by rice husk derived magnetic sorbents, Korean J. Chem. Eng. 33 (2016) 1416–1424. https://doi.org/10.1007/s11814-015-0248-y.
 S. Saadat, A.A. Hekmatzadeh, A.K. Jashni, Mathematical modeling of the Ni(II) removal from aqueous solutions onto pre-treated rice husk in fixed-bed columns: a comparison, Desalin. Water Treat. 57 (2016) 16907–16918. https://doi.org/10.1080/19443994.2015.1087877.
 K.G. Akpomie, F.A. Dawodu, Montmorillonite-rice husk composite for heavy metal sequestration from binary aqua media: a novel adsorbent, Trans. R. Soc. South Africa. 70 (2015) 83–88. https://doi.org/10.1080/0035919X.2014.984259.
 T.T. Pham, T.T.T. Mai, M.Q. Bui, T.X. Mai, H.Y. Tran, T.B. Phan, Nanostructured polyaniline rice husk composite as adsorption materials synthesized by different methods, Adv. Nat. Sci. Nanosci. Nanotechnol. 5 (2014) 15010. https://doi.org/10.1088/2043-6262/5/1/015010.
 I. Nhapi, N. Banadda, R. Murenzi, C.B. Sekomo, U.G. Wali, Removal of Heavy Metals from Industrial Wastewater Using Rice Husks, Open Environ. Eng. J. 4 (2011) 170–180. https://doi.org/10.2174/1874829501104010170.
 A.F.A. Tarmizi, K.K. Ong, W.M.Z.W. Yunus, A. Fitrianto, M.L. Japit, A.G. Hussin, C.C. Teoh, Sorption Isotherm Model of Zinc ( II ) onto Thermally Treated Rice Husk, Orien. J. Chem. 32 (2016).
 M.G. Pillai, I. Regupathi, M.H. Kalavathy, T. Murugesan, L.R. Miranda, Optimization and analysis of nickel adsorption on microwave irradiated rice husk using response surface methodology (RSM), J. Chem. Technol. Biotechnol. 84 (2009) 291–301. https://doi.org/10.1002/jctb.2038.
 Z. Asif, Z. Chen, Removal of arsenic from drinking water using rice husk, Appl. Water Sci. (2015). https://doi.org/10.1007/s13201-015-0323-x.
 G. Tan, H. Yuan, Y. Liu, D. Xiao, Removal of Cadmium from Aqueous Solution using Wheat Stem, Corncob, and Rice Husk, Sep. Sci. Technol. 46 (2011) 2049–2055. https://doi.org/10.1080/01496395.2011.573835.
 I. V. Sheveleva, A.N. Kholomeidik, A.V. Voit, N.P. Morgun, L.A.. Zemnukhova, Removal of metal ions with rice husk-based sorbents, Russ. J. Appl. Chem. 82 (2009) 1840–1844. https://doi.org/10.1134/S1070427209100188.
 S. Kamari, F. Ghorbani, Synthesis of magMCM-41 with rice husk silica as cadmium sorbent from aqueous solutions: parameters’ optimization by response surface methodology, Environ. Technol. 0 (2016) 1–18. https://doi.org/10.1080/09593330.2016.1237557.
 Z.C. Zhao PF, Guo X, The Removal of Elemental Mercury by Potassium Permanganate-modified Rice Husk Ash Sorbents, Energy Sources Part A Recover. Util. Environ. Eff. 34 (2012) 994–1003. https://doi.org/10.1080/15567031003735295.
 M.R.H. M. Haris, N.A. A. Wahab, C.W. Reng, B. Azahari, K. Sathasivam, The sorption of cadmium(II) ions on mercerized rice husk and activated carbon, Turkish J. Chem. 35 (2011) 939–950. https://doi.org/10.3906/kim-1103-62.
 W. Shan, Z. Zhao, D. Fang, Z. Lou, J. Xu, S. Yue, B.K. Biswas, Y. Xiong, Investigation on the selective adsorption of Mo(VI) by using modified rice husk and corn straw, Waste and Biomass Valorization. 4 (2013) 385–393. https://doi.org/10.1007/s12649-012-9149-z.
 P. Fongsatitkul, P. Elefsiniotis, D. Kitkaew, C. Rungsipanodorn, Use of rice husk ash as an admixture to remove chromium from a tannery waste, Water. Air. Soil Pollut. 220 (2011) 81–88. https://doi.org/10.1007/s11270-010-0736-y.
 L.S. Rocha, C.B. Lopes, J.A. Borges, A.C. Duarte, E. Pereira, Valuation of Unmodified Rice Husk Waste as an Eco-Friendly Sorbent to Remove Mercury: A Study Using Environmental Realistic Concentrations, Water. Air. Soil Pollut. 224 (2013) 1559. https://doi.org/10.1007/s11270-013-1599-9.
 J. Wongjunda, P. Saueprasearsit, Biosorption of Chromium (VI) Using Rice Husk Ash and Modified Rice Husk Ash, Env. Res. J. 4 (2010) 244-250.
 D. Sivakumar, Hexavalent chromium removal in a tannery industry wastewater using rice husk silica, Global J. Environ. Sci. Manage. 1 (2015) 27-40.
 M. Ajmal, R.A.K. Rao, S. Anwar, J. Ahmad, R. Ahmad, Adsorption studies on rice husk: removal and recovery of Cd(II) from wastewater, Biores. Tech. 2 (2003) 147-149.
 S. Sobhanardakani, R. Zandipak, Adsorption of Ni (II) and Cd (II) from Aqueous Solutions Using Modified Rice Husk, Iran J Health Sci 3 (2015) 1-9.
 T.K. Naiya, A.K. Bhattacharya, S.K. Das, Adsorptive removal of Cd(II) ions from aqueous solutions by rice husk ash, Env. Prog. Sust. Ener. 28 (2009) 535-546.
 A. Kausar, H.N. Bhatti, R.A. Sarfraz, M. Shahid, Prediction of optimum equilibrium and kinetic models for U(VI) sorption onto rice husk: comparison of linear and nonlinear regression methods, Desal. Water Treat. 52 (2014) 1495-1503.