Hydrogen Sulfide Gas Capture by Discarded Zn-MnO₂ Alkaline Batteries in Ambient Conditions

Battery waste-derived functional materials for the capture and removal of harmful gases

“…For capturing highly acidic gases like H 2 S, SO 2 , and NO 2 , the KOH electrolyte along with the ZnO–MnO 2 composite in the black mass is sufficient for gas oxidation, and thus, no pre-treatment is required. 21,22 However, for the thermal oxidation of gases like VOCs, researchers have treated the black mass with strong mineral/organic acids either to neutralize the KOH electrolyte 23–25 or to completely/selectively dissolve metals. 26,27 In some cases, a hydrometallurgical process like bioleaching is used to eliminate the use of strong mineral acids.…”

“…Theoretical calculations confirmed that ZnO was more reactive than MnO 2 , and black mass derived from a fully discharged battery is expected to show even higher adsorption capacity. 22 In a separate study, untreated black mass from Zn–MnO 2 batteries of different brands was used as catalysts for treating 100 ppm of SO 2 and NO 2 . These black mass samples have different phase composition, surface area, and alkalinity, which influenced their SO 2 uptake capacity.…”