Abstract

Hexavalent chromium (Cr(VI)) is a highly toxic metal that has been accused to be carcinogen with prolonged inhalation by humans and is toxic to aquatic life even at low concentrations. The objective of this work was to use water-soluble functionalized chitosan in the removal of chromate ions in aqueous solution. Functionalized chitosan was obtained by grafting molecules with quaternary ammonium groups in a heterogeneous process under alkaline conditions. Chitosan modified was characterized by FTIR, H-1-NMR spectroscopy, and TGA. The retention tests were carried out using the liquid-phase polymer-based retention technique (LPR) by means of the washing method, studying the effects of the variation of pH, interfering ions, and variations of hydrodynamic flow. The results showed 94.0% retention with regard to the modification of chitosan. For the removal studies, a trend in the retention percentages was presented as the pH increased, obtaining a maximum retention of 92.0% at pH 9.0. In studies of interfering ions, a decrease was found as the concentrations of interferent increased, obtaining the highest retention >70.0%. In conclusion, the functionalization of chitosan with quaternary ammonium groups in conjunction with the LPR technique is a great alternative in the removal of chromate ions and is friendly to the environment.