Hexavalent chromium removal from water using chitosan-Fe⁰nanoparticles

Abstract

Chitosan-Fe0 nanoparticles (chitosan-Fe0) were prepared using nontoxic and biodegradable chitosan as a stabilizer. Laboratory batch and column experiments were conducted to investigate the feasibility of using chitosan-Fe0 for in situ reductive removal of Cr(VI) from water. Batch kinetic tests indicated that the overall disappearance of Cr(VI) may include both physical adsorption of Cr(VI) onto the chitosan-Fe0 surface and subsequent reduction of Cr(VI) to Cr(III). The rate of reduction of Cr(VI) to Cr(III) can be expressed by a pseudo-first-order reaction kinetics and the rate constants increase with the increase in iron loading. Column experiments indicated that the chitosan-Fe0 were highly deliverable in the column. When the column was treated with Cr(VI) -contaminated deionized water, the removal capacity of chitosan-Fe0 was found to be about 32 mg Cr/g Fe(0). A 25% drop in the Cr(VI) removal capacity was found when treated with Cr(VI)-contaminated surface water.