Enhanced removal of arsenic from aqueous solution by novel red mud porous beads: batch and column experiments

Abstract

Arsenic contamination in groundwater and rivers has become a major problem around the world, and may cause severe environment pollution and human health problems. In this study, cost-efficient adsorbent red mud porous beads (RPB), using red mud – a kind of alumina industry by-product, was synthesized for adsorptive removal of arsenic(V) from aqueous solution. Kinetic studies showed that chemisorption mainly governed the adsorption process. The experimental data were fitted well using the Langmuir isotherm, and the equilibrium adsorption capacity for arsenic of 11.758 mg/g at pH = 7 conditions. The effect of pH showed that the pHpzc of RPB was 6.0 and at pH = 6 the removal rate reached nearly 100%. The removal rate decreased from 91.3% to 79.0% with increase in the initial concentration of arsenic from 2.5 to 20 mg/L. The adsorption performance from column studies illustrated that the velocity of flow and the initial concentration influenced the breakthrough time of the column. This study would facilitate the use of red mud, which can be fabricated into RPB, acting as a valuable adsorbent for removing arsenic in aqueous solutions. HIGHLIGHTS RPB was used as a valuable adsorbent for arsenic adsorption.; Chemisorption governed the adsorption process.; The experimental data were described well by Langmuir isotherm.; The velocity of flow and initial concentration influenced the breakthrough time.;

Keywords

• adsorption
• arsenic
• column experiments
• porous beads
• red mud