Purification mechanism of microbial metabolism in kitchen-oil wastewater enhanced by cationic vacancies on γ-Al₂O₃

The use of catalyst materials to mediate the enhancement of microbial degradation in wastewater is a new economic and energy saving breakthrough in water treatment technology. In this study, γ-Al₂O₃, which is commonly used as catalyst/carrier, is used as biological filler to treat kitchen-oil wastewater with low biodegradability, and the COD removal rate is about 50 %. It is found that the complexation of cationic vacancies on Al₂O₃ surface with extracellular polymeric substance (EPS) secreted by microorganisms in wastewater lead to the polarization of electron distribution on biofilm. The efficient degrading bacteria are enriched on reaction interface and obtain electrons to maintain electron dynamic balance by enhancing the transmembrane metabolism of pollutants. The aluminum vacancies on Al₂O₃ surface accelerate the microbial degradation of pollutants. The cationic vacancies in the structure of catalyst accelerate the acquisition of exogenous electrons by microorganisms without the addition of external energy, which provides a new idea for catalytic fillers to enhance wastewater degradation.