Efficient removal of arsenic from water using a granular adsorbent: Fe–Mn binary oxide impregnated chitosan bead

Abstract

A novel sorbent of Fe–Mn binary oxide impregnated chitosan bead (FMCB) was fabricated through impregnating Fe–Mn binary oxide into chitosan matrix. The FMCB is sphere-like with a diameter of 1.6–1.8mm, which is effective for both As(V) and As(III) sorption. The maximal sorption capacities are 39.1 and 54.2mg/g, respectively, outperforming most of reported granular sorbents. The arsenic was mainly removed by adsorbing onto the Fe–Mn oxide component. The coexisting SO42−, HCO3− and SiO32− have no great influence on arsenic sorption, whereas, the HPO42− shows negative effects. The arsenic-loaded FMCB could be effectively regenerated using NaOH solution and repeatedly used. In column tests, about 1500 and 3200 bed volumes of simulated groundwater containing 233μg/L As(V) and As(III) were respectively treated before breakthrough. These results demonstrate the superiority of the FMCB in removing As(V) and As(III), indicating that it is a promising candidate for arsenic removal from real drinking water.