Integrating anodic membrane diffusion/biodegradation with UV photolysis, Adsorptive oxidation by activation of peroxymonosulfate over activated carbon fiber based photo cathode in one reactor system for removing toluene gas

Abstract

Abstract Emissions of volatile organic compounds (VOCs) air pollutants adversely affected human health and air quality. A novel reactor is designed by a bio-anode chamber with a PVDF/CFC diffusion membrane module and a catalytic air cathode chamber with persulfate and activated carbon fiber (ACF) based photocathode. Peroxysulfate is activated to generate oxidizing species that promote toluene removal and oxidation together with UV photolysis and photo-electrochemical catalysis. This new reactor as air pollution control technique is able to continuously remove toluene gas from an air stream that sequentially flows through firstly the cathode chamber where UV photolysis, photo-electrochemical (PEC) oxidation are integrated with activation of peroxymonosulfate (PMS), then flows through the bio-anode chamber where adsorption/diffusion and biodegradation take place in microbial fuel cell (MFC). This integrated system exhibits high efficiency in toluene removal (∼95 %, ∼100 ppm toluene) with stable power output (cell voltage: 0.40 V) under UV light illumination. In addition, the existence of reactive species such as OH, O2− and SO4- radicals are confirmed by EPR tests. The results show that both ·OH and SO4- are involved in the toluene oxidative degradation with the addition of PMS, where SO4- plays a predominant role, indicating that combination of photolysis, cathodic adsorption/oxidation with anodic adsorption/diffusion and biodegradation provides a promising way for VOCs removal and simultaneous electricity generation at room temperature.