Study Of Indoor Benzene And Toluene Removal By Non-Thermal Discharge Coupled With Catalysis

Based on the former research in our laboratory, the production characteristic of O and N radical produced in needle matrix to plate corona discharge and their yield optimization under different experimental conditions were systematically investigated in this paper. Benzene and toluene are the common Volatile Organic Compounds (VOCs) in indoor air, the removal experiments of these two VOCs by needle matrix corona discharge coupled with catalysis was conducted. The operating parameters of indoor air purifier with needle matrix DC corona discharge as core purification unit were obtained. The removal mechanisms of benzene and toluene by needle matrix to plate corona discharge coupled with catalysis were analyzed using Gas Chromatography-Mass Spectrometer (GC-MS) and other gas analyzers, providing the theoretical support to the application of air purifier with needle matrix DC corona discharge as core technology.Firstly, the effects of discharge power, discharge polarity, electrode gap and relative humidity on the production of excited state O and N atom were investigated by optical emission spectroscopy. The production pattern and the relationship between macro parameters and micro characteristics of O and N atom were obtained under stable discharge condition. These results could provide comprehensive understanding to the law of radicals generated in needle matrix to plate corona discharge, and then also provide corresponding optimization parameters for indoor air purifier.Secondly, the technique of needle matrix to plate corona discharge was adopted to investigate the removal of benzene and toluene in a closed chamber. The effects of initial concentration, discharge power, electrode gap and relative humidity on the removal efficiencies of benzene and toluene were studied in positive and negative DC corona discharge. The removal patterns of benzene and toluene in this discharge mode were observed, and the operating parameters of purification device with needle matrix DC corona discharge as core purification unit were suggested. On this basis, plasma-photocatalysis, plasma-MnO2and plasma-photocatalysis-MnO2coupled purification systems were constructed. The variation trends of benzene and toluene removal efficiencies under different power and relative humidity were studied, and corresponding removal patterns of the two VOCs in different purification system were observed, providing the basis for air purifier of needle matrix DC corona discharge coupled with catalysis.Finally, the qualitative and/or quantitative analysis for benzene and toluene degradation products and harmful byproducts in different purification systems were conducted by GC-MS and other gas analyzers. Then, the removal mechanisms of benzene and toluene by needle matrix DC corona discharge coupled with catalysis were analyzed in detail, providing the theoretical support to air purifier design with needle matrix DC corona discharge as core technology.