Coupled catalytic-biodegradation of toluene over manganese oxide-coated catalytic membranes

Volatile organic compounds (VOCs) harm human health and the ecological environment. This work demonstrated manganese oxide catalytic membrane coupled to biodegradation of toluene in a catalytic membrane biofilm rector (CMBfR). Toluene removal efficiency in CMBfR was up to 91% in a 200-day operation. Manganese oxide combined to membrane biofilm reactor could promote degradation of toluene. Manganese oxide catalysts were characterized by XRD, Raman, XPS, and FT-IR. Raman and XPS spectra verified the existence of Mn defects, adsorbed oxygen species, and the oxygen vacancy, which was catalytic of toluene on the Mn oxides coated membranes significantly. Pseudomonas, Hydrogenophaga, Flavobacterium, Bacillus, Clostridium and Prosthecobacter were the dominant bacteria of toluene degradation. Mn oxides catalysis could degrade toluene into intermediate products; these products were entered into the biological phase eventually metabolized to CO₂ and H₂O. These results show that the catalytic membrane biofilm reactor is achievable and opens new possibilities for applying the catalytic membrane biofilm reactor to VOCs treatment.