Polyvinyl alcohol-stabilized granular Fe-Mn binary oxide as an effective adsorbent for simultaneous removal of arsenate and arsenite.

A novel granular Fe-Mn (GFM) binary oxide sorbent, with a diameter of approximate 2.0 mm and a length of 2.0-3.0 mm, was successfully prepared using extrusion granulation method in this study. The GFM sorbent is highly porous with a BET-specific surface area of 210.3 m/g. It shows high effectiveness in simultaneously adsorbing As(V) and As(III). The maximal sorption capacities for As(V) and As(III) are 33.2 and 50.7 mg/g at pH 7.0 ± 0.1, respectively, which are superior to most of granular sorbents reported in the literature. The present Ca, Mg, humic acids and fulvic acids do not have obvious influence on the arsenic sorption. But, coexisting anions affect negatively arsenic sorption in the following order: HPO  > SiO  > HCO  > SO . NaOH solution is an effective eluent for regeneration of the arsenic-loaded GFM. The GFM packed in the fixed-bed column can treat approximately 3400 and 6500 bed volumes of simulated groundwater containing 233 μg/L As(V) and As(III), respectively, before the arsenic concentration in the effluent reached a drinking water limit of 10 μg/L. The features of high effectiveness, selectivity and reusability make the GFM a potential alternative to remove simultaneously As(V) and As(III) from groundwater.