Performance of chitosan micro/nanoparticles to remove hexavalent chromium from residual water

ZARITZKY NOEMÍ; DIMA JIMENA

Advanced Nanomaterials for Water Engineering, Treatment, and Hydraulics

IGI Global book

Año: 2017; p. 262 - 288

Hexavalent chromiumCr(VI) is toxic to living systems and must be removed from wastewater. Chitosanis a cationic, biocompatible, biodegradable, biopolymer obtained from marinewastes. The performance of chitosan particles (CH) and chitosan nanoparticles(CHN) to remove Cr(VI) from aqueous solutions is discussed in the presentchapter. CHN were obtained by reticulation with tripolyphosphate (TPP), andphysico-chemically characterized. The performance of CHN decreased at higher pHdue to the cross-linking process with TPP. Langmuir isotherm described theequilibrium adsorption values and pseudo-second order rate provided the best fittingto the kinetic data. Chemical analysis to determine the oxidation state of the adsorbedCr, showed that Cr(VI) was adsorbed on CH particles without further reduction;in contrast Cr(VI) removed from the solution was reduced and bound to the CHNas Cr(III). Chitosan crosslinking was essential to adsorb Cr(VI) at pH<3 dueto the dissolution of CH in acid media.