Yttrium-Doped Iron Oxide Magnetic Adsorbent for Enhancement in Arsenic Removal and Ease in Separation after Applications

Abstract

Arsenic contamination is one of serious environmental problems in the world. In this study, an innovative yttrium-doped iron oxide magnetic adsorbent was synthesized through a simple precipitation method for better arsenic decontamination and ease in separation after the application. The adsorbent with a rough surface and porous structure was aggregated of nano-sized irregular particles after heat-drying procedure. The point of zero charge value of the adsorbent was about 7.0, giving good performance on the arsenate removal at weakly acidic and neutral conditions. The thermal gravimetric analysis, X-ray powder diffraction and X-ray photoelectron spectroscopy studies demonstrated that hydroxyl groups from goethite and amorphous species of the adsorbent were mainly responsible for the arsenic adsorption. The adsorption equilibrium of arsenate and arsenite was respectively established in 24 and 4 h. The maximum adsorption capacities of As(V) and As(III) at pH 7.0 were 170.48 and 84.22 mg-As/g, respectively. The better fit by the Freundlich isotherm indicated the mechanism of multi-layer adsorption for the removal. Our study demonstrated that the material would be suitable for treating arsenic-containing water with higher efficiency and ease in use.