Adsorption of Arsenic by Fe₃O₄, TiO₂, and Al₂O₃ Adsorbents

Abstract

Adsorption of arsenic (As(III) and As(V)) has been investigated, employing magnetite (Fe₃O₄), titania (TiO₂), and alumina (Al₂O₃) as adsorbents. Three kinds of adsorbents possess high adsorption ability for both As(III) and As(V) in acidic and neutral pH region, which indicates the all adsorbents are applicable for the As removal from common geothermal waters. The maximum adsorption amounts determined by Langmuir isotherms are order of Al₂O₃≈TiO₂>Fe₃O₄ in the case of As(III), and Al₂O₃>TiO₂>Fe₃O₄ in the case of As(V), respectively. These adsorption abilities are affected by both of hydroxyl groups on the surface and specific surface area of the powdered adsorbents. Chromatographic removal of As(III) from aqueous solution was performed by using a laboratory-scale column packed with the granulated adsorbents of Fe₃O₄, TiO₂ and Al₂O₃. The effective removal of As(III) from aqueous solution could be effectively achieved using granulated TiO₂ adsorbent in the three kinds of adsorbents, due to its high adsorption kinetics.