1. J. Kotas, Z. Stasicka, Chromium occurrence in the environment and methods of its speciation, Environ. Pollut., 107 (2000) 263–283.
  2. M. Dakiky, M. Khamis, A. Manassra, M. Mer’eb, Selective adsorption of Cr(VI) in industrial wastewater using low-cost abundantly available adsorbents, Adv. Env. Res., 6 (2002) 533– 540.
  3. A.P. Das, S. Mishra, Hexavalent chromium (VI): Environment pollutant and health hazard, JERAD, 2 (2008) 386–392.
  4. L.S. McNeill, J.E. Mclean, J.L. Parks, M.A. Edwards, Hexavalent chromium review, Part 2 : Chemistry, occurrence, and treatment, J. AWWA, 104 (2012) 395–405.
  5. J.E. McLean, L.S. McNeill, M. Edwards, J.L. Parks, Hexavalent chromium review, Part 1: Health effects, regulations, and analysis, J. AWWA, 104 (2012) E348–E357.
  6. S. Wilbur, H. Abadin, M. Fay, D. Yu, B. Tencza, L. Ingerman, J. Klotzbach, S. James, ATSDR, Atlanta, GA. (2012).
  7. M.J. Udy, History of Chromium, in: Udy, M.J., Ed., Chromium. Vol. I. Chemistry of Chromium and its Compounds, Reinhold, New York, 1956, pp. 1–13.
  8. X. Zhou, T. Korenaga, T. Takahashi, T. Moriwake, S. Shinoda, A process monitoring controlling system for the treatment of wastewater containing chromium(VI), Water Res., 27 (1993) 1049–1054.
  9. G. Tiravanti, D. Petruzzelli, R. Passino, Pretreatment of tannery waste waters by an ion exchange process for Cr(III) removal and recovery, Wat. Sci. Tech., 36 (1997) 197–207.
  10. J.C. Seaman, P.M. Bertsch, L. Schwallie, In situ Cr(VI) reduction within coarse-textured, oxide-coated soil and aquifer systems using Fe(II) solutions, Env. Sci. Tech., 33 (1999) 938– 944.
  11. M. Khamis, F. Jumean, N. Abdo, Speciation and removal of chromium from aqueous solution by white, yellow and red UAE sand, J. Hazard. Mater., 169 (2009) 948–952.
  12. S. Dahbi, M. Azzi, M. de la Guardia, Removal of hexavalent chromium from waste waters by bone charcoal, Fresenius J. Anal. Chem., 363 (1999) 404–407.
  13. N. Kongsricharoern, C. Polprasert, Chromium removal by a bipolar electrochemical precipitation process, Wat. Sci. Tech., 34 (1996) 109–116.
  14. K. Pagilla, L.W. Canter, Laboratory studies on remediation of chromium-contaminated soils, J. Environ. Eng., 125 (1999) 243–248.
  15. A.K. Chakravarti, S.B. Chowdhury, S. Chakrabarty, T. Chakrabarty, D.C. Mukherjee, Liquid membrane multiple emulsion process of chromium (VI) separation from waste waters, Colloids Surf. A: Physicochem. Eng. Asp., 103 (1995) 59–71.
  16. C.F. Lin, W. Rou, K.S. Lo, Treatment strategy for Cr(VI)-bearing wastes, Wat. Sci. Tech., 26 (1992) 2301–2304.
  17. B. Saha, C. Orvig, Biosorbents for hexavalent chromium elimination from industrial and municipal effluents, Coord. Chem. Rev., 254 (2010) 2959–2972.
  18. M. Solgi, T. Najib, S. Ahmadnejad, B. Nasernejad, Synthesis and characterization of novel activated carbon from medlar seed for chromium removal: Experimental analysis and modeling with artificial neural network and support vector regression, REFFIT, 3 (2017) 236–248.
  19. C.C. Kan, A.H. Ibe, K.K.P. Rivera, A.O. Arazo, M.D.G. de Luna, Hexavalent chromium removal from aqueous solution by adsorbents synthesized from groundwater treatment residuals, SER, 27 (2017) 163–171.
  20. F.H. Jumean, M.I. Khamis, Z.A. Sara, M.S. AbouRich, Concurrent removal and reduction of Cr (VI) by wool: short and long term equilibration studies, AJAC, 3 (2015) 1–11.
  21. A. Manassra, M. Khamis, T. Ihmied, M. El-Dakiky, Removal of chromium by continuous flow using wool packed columns, Electron. J. Environ. Agric. Food Chem., 9(3) (2010) 651–663.
  22. EPA method 7196A chromium, hexavalent (colorimetric).
  23. A. Ghosh, S.R. Collie, Keratinous materials as novel absorbent systems for toxic pollutants, Def. Sci. J., 64 (2014) 209–221.