Decomposition of Volatile Organic Compounds Using Surface-Discharge Microplasma Devices

摘要

Five volatile organic compounds (VOCs), n-octane, ethyl acetate, toluene, p-xylene and ethyl benzene, were decomposed with a newly developed surface-discharged microplasma device (SMD). The SMD consisted of a micropatterned electrode on one side of a mica substrate and an inductive electrode printed on the other side. A piezoelectric, transformed high-voltage (66.7 kHz, 3.5 kV) was applied to four SMDs placed in a batch reactor containing VOC in a gas mixture; the aim was to generate a surface-discharged microplasma through a localized dielectric barrier discharge for the decomposition of the VOCs. The decay in VOC concentration (C_(VOC)) during the discharge was evaluated by gas chromatography-mass spectrometry. For all the five VOCs, the decomposition rates can be treated as first-order reactions against C_(VOC) after a discharge time of 30min. Decomposition rate was dependent on the type of compound; the reaction rates of aromatic compounds were approximately twice as large as those of aliphatic compounds. Ion concentration measurements during the microplasma operation revealed that reaction rate showed linear relationship with the VOC ion concentration, which suggests that the ionization of the VOCs closely correlates with the rate-determining steps of decomposition reactions.