A Novel Dielectric Barrier Discharge Reactor With Photocatalytic Electrode Based On Sintered Metal Fibers For Abatement Of Paint Waste Gas

The synergy between NTP (Non-thermal Plasma) and photo catalysts is one of NTP technology extensions and innovations. In this work, an innovative reactor combining SMF (sintered metal fiber) catalyst with DBD (dielectric barrier discharge) was designed. SMF catalyst was used as electrode as well as catalyst and it took full advantage of short-lived active species generated by NTP. In order to effectively abate xylene, using nano-TiO2modified SMF electrodes seemed to be a promising alternative approach. The influence of various reaction parameters and the synergy between DBD and SMF catalyst were investigated.The reactor using the nano-TiO2/SMF electrode shows much better performance in abating xylene compared with reactors using other electrodes such as resistance wire or SMF. The conversion ratio of xylene reaches92.7%in the novel reactor at a relatively voltage (23.6kV). This ratio was much higher than the conversion ratios of xylene in the traditional reactors with resistance wire or SMF electrodes, which was～64.7%. The selectivity of CO2of the reactor using the nano-TiO2/SMF electrode (300pps,23.6kV) was observed to be86.6%, which is about twice as large as that of a traditional reactor using a resistance wire electrode. If a traditional DBD reactor is replaced by the novel reactor, at the same specific input energy, the energy yield could increase from0.268to0.384mg/kJ.The effects of SMF loading capacity, pulse frequency, carrier gas and the humidity on the performance of this novel DBD reactor were also studied. The optimized loading capacity was found by experiments. When using the nano-TiO2/SMF electrode, the conversion of xylene was improved at a constant frequency. The removal efficiency of xylene at23.6kV increased to83.5%,90.8%and92.7%, versus58.8%,62.2%and64.7%without the nano-TiO2/SMF electrode from100pps to300pps. The increase in the frequency and peak voltage could enhance the selectivity of CO2too. Even though the removal ratio of xylene was the lowest among the three frequencies (100pps frequency), the corresponding EY (0.909mg/kJ) was the highest one among the frequencies. The effect of N2was investigated, it showed that N2had an influence on photo catalyst activated.In addition, scanning electron microscopy (SEM), X-ray photoelectron spectroscopy (XPS) and ultrasound adherence tests were performed for the characterization of the nano-TiO2/SMF. The SEM images showed that nano-TiO2had been successfully deposited onto the porous SMF surface. Both ultrasound treatments and XPS results indicate a strong adherence of nano-TiO2on SMF with the modified anodic oxidation method. Ti3+helped explain why the nano-TiO2/SMF electrode has significantly enhanced performance in the photo catalysis process.