Removal of hexavalent chromium using a novel cross linked xanthated chitosan.

Suitability of a novel cross linked, chemically modified chitosan as highly efficient adsorbent for the recovery of toxic chromium(VI) was studied. After cross linking with glutaraldehyde, xanthate group was grafted onto the back bone of chitosan. Sorption was found to be both pH and concentration dependent, with pH 3 being the optimum value. Both, chemically modified beads (CMCB) and flakes (CMCF) followed a pseudo-second-order kinetics with a rate constant of 2.037 and 4.639 g/mg/min, respectively. The equilibrium data followed the Langmuir isotherm model with maximum capacities of 625 mg/g and 256.4 mg/g and for CMCF and CMCB respectively. Desorption studies revealed the reusability of the sorbent for at least 10 cycles without any significant change in adsorption capacities.