Study on the adsorption of arsenate in aqueous solution by Tay Nguyen red mud after separating the aluminium and other soluble components in alkaline solution

Tay Nguyen red mud which is the waste material of alumina production from bauxite, contains some metal oxides such as iron oxide, aluminum oxide, silicon dioxide, titanium dioxide…in which iron oxide content ranges from 45% to 55% accounting for its red colour. The iron oxide and oxyhydroxides (FeOOH) have high adsorption ability for heavy metals such as As, Pb,Cu, Cd….In this study, sodium solution was used to separate aluminum oxide and other metals which are soluble in alkaline solution, from Tay Nguyen red mud. The new material containing only iron oxide, iron oxyhydroxide which are not soluble in alkaline solution was washed with distilled water until the pH of 7, then was dried at 60oC for 24h. The new material was used to adsorb As(V) in aqueous solution. The results showed that the optimum adsorption reached when pH was 5, the equilibrium time of 90 minutes and the adsorption capacity determined from Langmuir isothermal equation reached 7.57 mg/g for As(V).