1. A.A. Alqadami, M. Naushad, Z.A. Alothman, A.A. Ghfar, Novel metal-organic framework (MOF) based composite material for the sequestration of U(VI) and Th(IV) metal ions from aqueous environment, ACS Appl. Mater. Interfaces, 9 (2017) 36026–36037.
  2. M. Naushad, T. Ahamad, B.M. Al-Maswari, A. Abdullah, A. Saad, M. Alshehri, Nickel ferrite bearing nitrogen-doped mesoporous carbon as efficient adsorbent for the removal of highly toxic metal ion from aqueous medium, Chem. Eng. J., 330 (2017) 1351–1360.
  3. World Health Organization Division of Operational Support in Environmental, Guidelines for Drinking-Water Quality. Vol. 2, Health Criteria and Other Supporting Information : Addendum, 1998. Available at:
  4. A.K. Shanker, B. Venkateswarlu, Chromium: Environmental Pollution, Health Effects and Mode of Action, Encyclopedia of Environmental Health, Elsevier, J.O. Nriagu, 2011, pp. 650–659.
  5. J.W. Moore, C.L. Stanitski, Chemistry: The Molecular Science, Cengage Learning, 2014, 1272 pages.
  6. D.E. Kimbrough, Y. Cohen, A.M. Winer, L. Creelman, C. Mabuni, A critical assessment of chromium in the environment, Crit. Rev. Environ. Sci. Technol., 29 (1999) 1–46.
  7. G. Agarwal, H. Bhuptawat, S. Chaudhari, Biosorption of aqueous chromium(VI) by Tamarindus indica seeds, Bioresour. Technol., 97 (2006) 949–956.
  8. D. Mohan, C.U. Pittman, Activated carbons and low cost adsorbents for remediation of tri- and hexavalent chromium from water, J. Hazard. Mater., 137 (2006) 762–811.
  9. L. Sellaoui, F.E. Soetaredjo, S. Ismadji, E.C. Lima, G.L. Dotto, A.B. Lamine, A. Erto, New insights into single-compound and binary adsorption of copper and lead ions on a treated sea mango shell: experimental and theoretical studies, PCCP, 19 (2017) 25927–25937.
  10. A. Kumar, A. Kumar, G. Sharma, A.H. Al-Muhtaseb, M. Naushad, A.A. Ghfar, F.J. Stadler, Quaternary magnetic BiOCl/g-C3N4/Cu2O/Fe3O4 nano-junction for visible light and solar powered degradation of sulfamethoxazole from aqueous environment, Chem. Eng. J., 334 (2018) 462–478.
  11. A. Kumar, C. Guod, G. Sharma, D. Pathania, M. Naushad, S. Kalia, P. Dhiman, Magnetically recoverable ZrO2/Fe3O4/chitosan nanomaterials for enhanced sunlight driven photoreduction of carcinogenic Cr(VI) and dechlorination and mineralization of 4-chlorophenol from simulated waste water, RSC Adv., 6 (2016) 13251–13263.
  12. A. Dąbrowski, Adsorption—from theory to practice, Adv. Colloid Interface Sci., 93 (2001) 135–224.
  13. R. Han, J. Zhang, W. Zou, J. Shi, H. Liu, Equilibrium biosorption isotherm for lead ion on chaff, J. Hazard. Mater., 125 (2005) 266–271.
  14. L. Sellaoui, D.S.P. Franco, G.L. Dotto, É.C. Lima, A.B. Lamine, Single and binary adsorption of cobalt and methylene blue on modified chitin: application of the Hill and exclusive extended Hill models, J. Mol. Liq., 233 (2017) 543–550.
  15. Y. Li, B. Zhao, L. Zhang, R. Han, Biosorption of copper ion by natural and modified wheat straw in fixed-bed column, Desal. Wat. Treat., 51 (2013) 5735–5745.
  16. N. Sivarajasekar, K. Balasubramani, N. Mohanraj, J.P. Maran, S. Sivamani, P.A. Koya, V. Karthik, Fixed-bed adsorption of atrazine onto microwave irradiated Aegle marmelos Correa fruit shell: statistical optimization, process design and breakthrough modelling, J. Mol. Liq., 241 (2017) 823–830.
  17. B. Preetha, T. Viruthagiri, Batch and continuous biosorption of chromium(VI) by Rhizopus arrhizus, Sep. Purif. Technol., 57 (2007) 126–133.
  18. V.K. Gupta, A. Rastogi, Biosorption of hexavalent chromium by raw and acid-treated green alga Oedogonium hatei from aqueous solutions, J. Hazard. Mater., 163 (2009) 396–402.
  19. K. Kayalvizhi, K. Vijayaraghavan, M. Velan, Biosorption of Cr(VI) using a novel microalga Rhizoclonium hookeri: equilibrium, kinetics and thermodynamic studies, Desal. Wat. Treat., 56 (2015) 194–203.
  20. R. Senthilkumar, K. Vijayaraghavan, J. Jegan, M. Velan, Batch and column removal of total chromium from aqueous solution using Sargassum polycystum, Environ. Prog. Sustainable Energy, 29 (2010) 334–341.
  21. X. Wang, Z. Li, S. Tao, Removal of chromium (VI) from aqueous solution using walnut hull, J. Environ. Manage., 90 (2009) 721–729.
  22. V.K. Gupta, D. Pathania, S. Agarwal, S. Sharma, Removal of Cr(VI) onto Ficus carica biosorbent from water, Environ. Sci. Pollut. Res., 20 (2013) 2632–2644.
  23. G. Sharma, M. Naushad, A.H. Al-Muhtaseb, A. Kumar, M.R. Khan, S. Kalia, S.M. Bala, A. Sharma, Fabrication and characterization of chitosan-crosslinked-poly(alginic acid) nanohydrogel for adsorptive removal of Cr(VI) metal ion from aqueous medium, Int. J. Biol. Macromol., 95 (2017) 484–493.
  24. S.M. Ickert‐Bond, Cuticle micromorphology of Pinus krempfii Lecomte (Pinaceae) and additional species from Southeast Asia, Int. J. Plant Sci., 161 (2000) 301–317.
  25. H. Choudhury, Development of an Embryogenic System for Mass Propagation of Pinus kesiya Royle ex Gord and Field Performance of the Regenerants, Ph.D. Thesis, North-Eastern Hill University, Shillong, Meghalaya, 2002.
  26. K. Li, S. Tian, J. Jiang, J. Wang, X. Chen, F. Yan, Pine cone shellbased activated carbon used for CO2 adsorption, J. Mater. Chem. A, 4 (2016) 5223–5234.
  27. S. Rangabhashiyam, N. Selvaraju, Evaluation of the biosorption potential of a novel Caryota urens inflorescence waste biomass for the removal of hexavalent chromium from aqueous solutions, J. Taiwan Inst. Chem. Eng., 47 (2015) 59–70.
  28. N. Saranya, E. Nakeeran, M.S.G. Nandagopal, N. Selvaraju, Optimization of adsorption process parameters by response surface methodology for hexavalent chromium removal from aqueous solutions using Annona reticulata Linn peel microparticles, Water Sci. Technol., 75 (2017) 2094–2107.
  29. E. Nakkeeran, N. Saranya, M.S.G. Nandagopal, A. Santhiagu, N. Selvaraju, Hexavalent chromium removal from aqueous solutions by a novel powder prepared from Colocasia esculenta leaves, Int. J. Phytorem., 18 (2016) 812–821.
  30. G. Gebrehawaria, A. Hussen, V.M. Rao, Removal of hexavalent chromium from aqueous solutions using barks of Acacia albida and leaves of Euclea schimperi, Int. J. Environ. Sci. Technol., 12 (2015) 1569–1580.
  31. R. Jin, Y. Liu, G. Liu, T. Tian, S. Qiao, J. Zhou, Characterization of product and potential mechanism of Cr(VI) reduction by anaerobic activated sludge in a sequencing batch reactor, Sci. Rep., 7 (2017) 1681.
  32. S. Kuppusamy, P. Thavamani, M. Megharaj, K. Venkateswarlu, Y.B. Lee, R. Naidu, Potential of Melaleuca diosmifolia leaf as a low-cost adsorbent for hexavalent chromium removal from contaminated water bodies, Process Saf. Environ. Prot., 100 (2016) 173–182.
  33. V. Nair, A. Panigrahy, R. Vinu, Development of novel chitosan–lignin composites for adsorption of dyes and metal ions from wastewater, Chem. Eng. J., 254 (2014) 491–502.
  34. R. Saha, B. Saha, Removal of hexavalent chromium from contaminated water by adsorption using mango leaves (Mangifera indica), Desal. Wat. Treat., 52 (2014) 1928–1936.
  35. G. Moussavi, B. Barikbin, Biosorption of chromium(VI) from industrial wastewater onto pistachio hull waste biomass, Chem. Eng. J., 162 (2010) 893–900.
  36. I. Ullah, R. Nadeem, M. Iqbal, Q. Manzoor, Biosorption of chromium onto native and immobilized sugarcane bagasse waste biomass, Ecol. Eng., 60 (2013) 99–107.
  37. I. Langmuir, The adsorption of gases on plane surfaces of glass, mica and platinum, J. Am. Chem. Soc., 40 (1918) 1361–1403.
  38. N. Sivarajasekar, R. Baskar, T. Ragu, K. Sarika, N. Preethi, T. Radhika, Biosorption studies on waste cotton seed for cationic dyes sequestration: equilibrium and thermodynamics, Appl. Water Sci., 7 (2017) 1987–1995.
  39. H. Freundlich, Über die Adsorption in Lösungen, Z. Phys. Chem., 57U (1907) 385–470.
  40. K. Sing, Reporting physisorption data for gas/solid systems with special reference to the determination of surface area and porosity (Recommendations 1984), Pure Appl. Chem., 57 (1985) 603–619.
  41. S. Aytas, D.A. Turkozu, C. Gok, Biosorption of uranium(VI) by bi-functionalized low cost biocomposite adsorbent, Desalination, 280 (2011) 354–362.
  42. S. Lagergren, Zurtheorie der sogenannten adsorption gelosterstoffe, Kongl. Sv.Vet. Akad. Handlingar, 24 (1898) 1–39.
  43. Y.S. Ho, G. McKay, Pseudo-second order model for sorption processes, Process Biochem., 34 (1999) 451–465.
  44. W. Weber, J. Morris, Advances in Water Pollution Research: Removal of Biologically Resistant Pollutants from Waste Waters by Adsorption, Proceedings of the International Conference On Water Pollution Symposium, vol. 2, 1962, pp. 231–266.
  45. S. Rangabhashiyam, N. Selvaraju, Adsorptive remediation of hexavalent chromium from synthetic wastewater by a natural and ZnCl2 activated Sterculia guttata shell, J. Mol. Liq., 207 (2015) 39–49.
  46. A.S. Özcan, S. Tunali, T. Akar, A. Özcan, Biosorption of lead(II) ions onto waste biomass of Phaseolus vulgaris L., estimation of the equilibrium, kinetic and thermodynamic parameters, Desalination, 244 (2009) 188–198.
  47. H.N. Tran, S.-J. You, H.-P. Chao, Thermodynamic parameters of cadmium adsorption onto orange peel calculated from various methods: a comparison study, J. Environ. Chem. Eng., 4 (2016) 2671–2682.
  48. A. Kumar, H.M. Jena, Adsorption of Cr(VI) from aqueous solution by prepared high surface area activated carbon from Fox nutshell by chemical activation with H3PO4, J. Environ. Chem. Eng., 5 (2017) 2032–2041.
  49. H. Gao, Y. Liu, G. Zeng, W. Xu, T. Li, W. Xia, Characterization of Cr(VI) removal from aqueous solutions by a surplus agricultural waste—rice straw, J. Hazard. Mater., 150 (2008) 446–452.
  50. M. Dakiky, M. Khamis, A. Manassra, M. Mer’eb, Selective adsorption of chromium(VI) in industrial wastewater using low-cost abundantly available adsorbents, Adv. Environ. Res., 6 (2002) 533–540.
  51. Y. Yi, J. Lv, Y. Liu, G. Wu, Synthesis and application of modified Litchi peel for removal of hexavalent chromium from aqueous solutions, J. Mol. Liq., 225 (2017) 28–33.
  52. J. Ponou, J. Kim, L.P. Wang, G. Dodbiba, T. Fujita, Sorption of Cr(VI) anions in aqueous solution using carbonized or dried pineapple leaves, Chem. Eng. J., 172 (2011) 906–913.
  53. R.A.K. Rao, S. Ikram, M.K. Uddin, Removal of Cr(VI) from aqueous solution on seeds of Artimisia absinthium (novel plant material), Desal. Wat. Treat., 54 (2015) 3358–3371.
  54. E. Oguz, Adsorption characteristics and the kinetics of the Cr(VI) on the Thuja orientalis, Colloids Surf., A, 252 (2005) 121–128.
  55. F. Mutongo, O. Kuipa, P.K. Kuipa, Removal of Cr(VI) from aqueous solutions using powder of potato peelings as a low cost sorbent, Bioinorg. Chem. Appl., 2014 (2014) 1–7.