A novel array of double dielectric barrier discharge combined with Ti Co catalyst to remove high-flow-rate toluene: Performance evaluation and mechanism analysis

A novel array double dielectric barrier discharge (ADDBD) combined with a TiO2/Al2O3-Co3O4/AC (Ti Co) catalyst was applied to remove toluene. The effects of catalyst setting distance, catalyst combination mode, and process factors (including specific input energy, initial toluene concentration, and relative humidity) were investigated in terms of the toluene degradation efficiency (ηtoluene) and the selectivity of CO2 (SCO2). When the specific input energy was 65 J·L−1, the initial toluene concentration was 100 mg·m−3, and the relative humidity was 30%, the highest ηtoluene of 72% and SCO2 of 44% could be achieved with TiO2/Al2O3 10 cm and Co3O4/AC 20 cm downstream of the ADDBD. Based on the determination of active substances (e.g., O3, OH) and the catalyst activation mode, a synergistic effect of active substances and photon between the ADDBD and the Ti Co catalyst was proposed for the removal of toluene. Finally, the biodegradability and toxicity of the outlet gas were evaluated, and the results showed that the outlet gas was more convenient for subsequent biopurification and less toxic to the surroundings after the treatment by the ADDBD combined with the Ti Co catalyst.