Comparison of Arsenic Adsorption on Goethite and Amorphous Ferric Oxyhydroxide in Water

Except for the specific surface area and pore size, the hydroxyl groups on the surface of the ferric oxides were determined as the key factor in arsenic adsorption in this study. Two synthetic mesoporous ferric oxides, amorphous ferric oxyhydroxide (AFO) and goethite, were used to adsorb As(III) and As(V) in aqueous solution. The experimental results showed that the AFO had a higher hydroxyl group density, resulting in a higher arsenic adsorption capacity than that on the goethite for both As(III) and As(V). Also, it was found that the adsorption of As(III) on both the goethite and AFO was faster than that of As(V), and the adsorption rate fitted the pseudo-second-order kinetics. The findings indicated a promising modification of adsorbents for arsenic remediation.