Performance of Fe-C catalyst in improving mass transfer efficiency in a wet scrubber for ozone-oxidizing chlorobenzene

The degradation of chlorinated volatile organic compounds （CVOCs） in a wet scrubber using ozone （O3） is primarily limited by the gas-liquid mass transfer efficiencies of O3 and CVOCs. In this research， a catalyst prepared by loading ferrous oxide onto activated carbon， named Fe-C， was used to boost the gas-liquid mass transfer of O3 and a typical CVOCs specie， chlorobenzene （CB）. The effects of Fe-C dosage， inlet concentration， and gas flow rate on the mass transfer of O3 and CB were investigated， and the mechanism of the simultaneous mass transfer of O3 and CB enhanced by Fe-C was revealed. The results showed that injecting O3 or CB into the wet scrubber alone caused the mass transfer coefficients to increase with the inlet concentration， and these coefficients initially rose and then decreased as the Fe-C dosage and gas flow rate increased. For both O3 and CB， the best mass transfer effect was achieved with an Fe-C dosage of 2.0 g/L and a gas flow rate of 500 mL/min. The mass transfer enhancement factors of O3 and CB were 19.73 and 10.91， respectively， at the Fe-C dosage of 2.0 g/L. When O3 and CB were simultaneously fed into the wet scrubber， the mass transfer of CB was further enhanced， and the CB mass transfer enhancement factor E could reach 12.87 at the Fe-C dosage of 2.0 g/L. The shuttle effect of Fe-C enhanced the mass transfer of CB and O3 between gas and liquid phases. Through converting O3 into ∙OH and ∙O2-， the Fe-C catalyst promoted the degradation of CB in the solution.