Arsenic removal from aqueous solutions by adsorption on red mud

Abstract Use of red mud, which is a waste product from bauxite processing, has been explored as an alternate adsorbent for arsenic in this study. The tests showed that the alkaline aqueous medium (pH 9.5) favored the removal of As(III), whereas the pH range from 1.1 to 3.2 was e€ective for As(V) removal. The process of arsenic adsorption follows a ®rst-order rate expression and obeys the Langmuir's model. It was found that the adsorption of As(III) was exothermic, whereas As(V) adsorption was endothermic. ...