Application of zerovalent iron impregnated chitosan-caboxymethyl-β-cyclodextrin composite beads as arsenic sorbent

Abstract

Nano zerovalent iron impregnated chitosan-carboxymethyl β-cyclodextrin complex has been successfully tested for arsenic removal. Addition of chitosan enhances the stability of Fe0 particles and the carboxymethyl β-cyclodextrin gives the composite more active sites to interact with the target ions. Removal of arsenic(III) and arsenic(V) was studied through batch adsorption at pH 6.0 under equilibrium and dynamic conditions. Prepared beads were characterized by FT-IR, SEM, BET and XPS. The rate of reduction can be expressed by pseudo-second-order reaction kinetics plus the equilibrium data were well fitted to Langmuir adsorption models. Equilibrium is achieved after 3h and As(III) and As(V) were reduced to <20μg/L which accounts 99% of the total removal below the Bangladesh standard (50μg/L). The adsorption capacity was calculated from Langmuir model and found to be 18.51mg/g and 13.51mg/g for As(III) and As(V), respectively. The adsorbent can be separated magnetically and thus reused successfully for the removal of total inorganic arsenic from water. So, this adsorbent can be a potential material for the remediation of contaminated surface and ground water.