Use of bauxite residue (red mud) as a low cost sorbent for sulfide removal in polluted water remediation

Abstract

Abstract:Sulfide is an important pollutant in aqueous systems. Sulfide removal from polluted waters is required prior to discharge. Red mud (RM) is a solid waste of bauxite processing that is rich in reactive iron oxides and consequently has the potential to be used to remove sulfide from aqueous systems. A series of experiments were undertaken using raw and sintered RM to remove sulfide from waters. RM was highly efficient at sulfide removal (average 75% sulfide removal at initial concentration of ~5 mg L -1 , with 500 mg L -1 RM addition) due to both physical adsorption (high specific area) and chemical reaction (with amorphous Fe). Sintered RM, which has a lower surface area and lower mineral reactivity, was much less efficient at removing sulfide (~20% removal under equivalent experimental conditions). Furthermore, concomitant metal release from raw RM was lower than for sintered RM during the sulfide removal process. The results showed that raw RM is a potentially suitable material for sulfide removal from polluted waters and consequently could be used as a low cost alternative treatment in certain engineering applications.

Simultaneous Removal of SO2 and NOX by a Combination of Red Mud and Coal Mine Drainage

“…Therefore, RM has been widely investigated for environmental-friendly and economically efficient applications. The various applications that have been studied mainly include the use of RM in building, pollution control, and metal recovery (Huang et al, 2016;Sheng et al, 2016). RM is mainly composed of several metal oxides, and the calcium oxide (CaO) content of Chinese RM is much higher than that in other countries (Wang et al, 2008;Liu et al, 2014).…”