Kinetic studies on sorption of Cr(VI) and Cu(II) ions by chitin, chitosan and Rhizopus arrhizus

This work focuses on Cr(VI), Cu(II) sorption kinetics by chitin, a naturally occurring material, chitosan, the deacetylated form of chitin, and Rhizopus arrhizus, a filamentous fungus containing chitin and chitosan as a main cell wall component. The aim of this study is to understand the mechanisms that govern Cr(VI) and Cu(II) removal, and find an appropriate model for the kinetics of removal in a batch reactor. In order to investigate the mechanism of sorption and potential rate controlling steps, the pseudo-first, first, pseudo-second order kinetic models and the Elovich equation have been used to test experimental data. For all of the metal-biosorbent systems studied, the pseudo-second order rate expression provided the best fitting kinetic model. (C) 2002 Elsevier Science B.V. All rights reserved.