Enhanced Arsenic Removal from Water by Activated Red Mud Based on Hydrated Iron(III) and Titan(IV) Oxides

Abstract

In this study, acid heat-activated neutralized red mud (AB) was promoted as an efficient sorbent for the removal of inorganic arsenic from water. Three sorbents: neutralized red mud (Bauxsol), acid-treated Bauxsol (aBauxsol), and AB were investigated for arsenic removal. The sorption of arsenic on these adsorbents was studied as a function of contact time, initial arsenic concentration, and adsorbent dosage. The Langmuir isotherm was the best-fit adsorption isotherm model for the experimental data. The adsorption capacity of the activated red mud for As(V) was found to be 1.49 mg g(-1) at a pH of water of 7.0. It was observed that AB at a dose of 6.0 gL(-1) could effectively remove As(III) and As(V) from water. Anion interference on a molar basis was found to follow the order: phosphate interference was higher than sulfate interference, which was higher than bicarbonate interference.