Bioleaching the Valuable Metals from Electroplating Sludge Through the Membrane Biological Reactor

The growing global concern regarding metal resource scarcity has spurred worldwide interest in recovering valuable metals from secondary sources, establishing this field as a prominent research priority. This work introduces the membrane bioreactors (MBR) was used to continuously concentrate the valuable metals from the electroplating sludge through a novel cycle of regeneration-bioleaching. The bioleaching acidophilic bacteria was applied in 10 m³ membrane bioreactor. After membrane separation between acidophilic bacteria and acidic liquid to obtain a large amount of acidic liquid without bacterias and it was applied to bioleaching electroplating sludge. The acidic bioleaching liquor from electroplating sludge can be recycled to the membrane bioreactor (MBR), where bacteria regenerate the acid. This cyclic process enriches the target metals and achieved 100% extraction of nickel, copper, and zinc after eight MBR cycles, a performance superior to chemical leaching. This study provides a demonstrative framework for the industrial application of MBR-based bioleaching, with potential for extension to other types of hazardous waste.