Fu, F. and Wang, Q., “Removal of heavy metal ions from wastewaters: A review”, Environmental Management., 92, 407 (2010).
 Wang, P. and Lo, I., “Synthesis of mesoporous magnetic g-Fe2O3 and its application to Cr(VI) removal from contaminated water”, Water Research, 43 (15), 3727 (2009).
 Alyüz, B. and Veli, S., “Kinetics and equilibrium studies for the removal of nickel and zinc from aqueous solutions by ion exchange resins”, Journal of Hazardous Materials, 167, 482 (2009).
 Rahmani, A., Zavvar Mousavi, H. and Fazli, M., “Effect of nanostructure alumina on adsorption of heavy metals”, Desalination, 253, 94 (2010).
 Ming, H., Zhang, Sh., Bingcai, P. and Zhang,W., “Heavy metal removal from water/wastewater by nanosized metal oxides: A review”, Journal of Hazardous Materials., 211–212, 317 (2012).
 Deliyanni, E. A., Peleka, K. A. and Matis, K. A., “Modeling the sorption of metal ions from aqueous solution by iron-based adsorbents”, Journal of Hazardous Materials., 172, 550 (2009).
 Xu, P., Zeng, G., Huang, D. and Feng, C. L., “Use of iron oxide nanomaterials in wastewater treatment: A review”, Science of the Total Environment., 424, 1 (2012).
 Boyer, C., Wittaker, M., Bulmus, V., Liu, J. and Davis, T., “The design and utility of polymer-stabilized iron-oxide nanoparticles for nanomedicine applications”, NPG Asia Mater., 2, 23 (2010).
 Dias, A., Hussain, A., Marcos, A. S. and Roque, A., “A biotechnological perspective on the application of iron oxide magnetic colloids modified with polysaccharides”, Biotechnology Advances., 29, 142 (2011).
 Hu, J., Chen, G. and Lo, L., “Removal and recovery of Cr(VI) from wastewater by maghemite nanoparticles”, Water Research., 39, 4528 (2005).
 Chowdhury, S. A. and Yanful, E. K., “Arsenic and chromium removal by mixed magnetiteemaghemite nanoparticles and the effect of phosphate on removal”, Journal of Environmental Management, 91(11), 2238 (2010).
 Wang, P. and Lo, I., “Synthesis of mesoporous magnetic γ-Fe2O3 and its application to Cr(VI) removal from contaminated water”, Water Research, 43 (15), 3727 (2009).
 Pang, Y., Zeng, G., Tang, L., Zhang, Y., Lei, X. and Li, Z., “Preparation and application of stability enhanced magnetic nanoparticles for rapid removal of Cr(VI)”, Chemical Engineering Journal, 175, 222 (2011).
 Anbia, M. and Mohammadi, N., “A fast and efficient method for the removal of hexavalent chromium from aqueous solutions”, Journal of Porous Materials, 18, 13 (2011).
 Shen, H., Pan, Sh., Zhang, Y., Huang, X. and Gong, H., “A new insight on the adsorption mechanism of amino-functionalized nano-Fe3O4 magnetic polymers in Cu(II), Cr(VI) co-existing water system”, Chemical Engineering Journal, 183, 180 (2012).
 Badruddoza, A. Z., Shawn, Z. B. Z., Rahman, M. T., Hao, K. W., Hidajat, K. and Shahab Uddin, M., “Ionically modified magnetic nanomaterials for arsenic and chromium removal from water”, Chemical Engineering Journal, 225, 607 (2013).
 Yuan, P., Fan, M., Yang, D., He, H., Liu, D. and Yuan, A., “Montmorillonite-supported magnetite nanoparticles for the removal of hexavalent chromium [Cr(VI)] from aqueous solutions”, Journal of Hazardous Materials, 166 (2-3), 821 (2009).
 Yuan, P., Liu, D., Fan, M., Yang, D., Zhu, R. and Ge, F., “Removal of hexavalent chromium [Cr(VI)] from aqueous solutions by the diatomite-supported/unsupported magnetite nanoparticles”, Journal of Hazardous Materials, 173 (1-3), 614 (2010).
 Zhang, Z. J., Chen, X. Y., Wang, B. N. and Shi, C. W., “Hydrothermal synthesis and self-assembly of magnetite (Fe3O4) nanoparticles with the magnetic and electrochemical properties”, Journal of Crystal Growth, 310 (24), 5453 (2008).
 Lee, H. Y., Lim, N. H., Seo, J. A., Yuk, S. H., Kwak, B. K. and Khang, G., “Preparation and magnetic resonance imaging effect of polyvinylpyrrolidone-coated iron oxide nanoparticles”, Journal of Biomedical Materials Research, 79B (1), 142 (2006).
 Zhang, Z., Zhao, B. and Hu, L., “PVP protective mechanism of ultrafine silver powder synthesized by chemical reduction processes”, Solid State Chemistry, 121, 105 (1996).
 Huang, S. H. and Chen, D. H., “Rapid removal of heavy metal cations and anions from aqueous solutions by an amino-functionalized magnetic nano-adsorbent”, Journal of Hazardous Materials, 163, 174 (2009).
 Pang, Y., Zeng, G., Tang, L. and Zhang, Y., “Preparation and application of stability enhanced magnetic nanoparticles for of Cr(VI)”, Chemical Engineering Journal., 175, 222 (2011).
 Wang, H., Qiao, X., Chen, J., Wang, X. and Ding, S., “Mechanisms of PVP in the preparation of silver nanoparticles”, Materials Chemistry and Physics., 94, 449 (2005).