Decomposition of Toluene with Surface-Discharge Microplasma Device

Abstract

A surface-discharge microplasma device (SMD) was developed for the decomposition of volatile organic compounds (VOCs) in the gas phase. The device is composed of a microscale-patterned electrode, a dielectric substrate, and a ground electrode. As a result of localized dielectric barrier discharge (DBD), surface-discharge microplasma was generated when a piezoelectric-transformed high voltage (66.7 kHz, 3.5 kV) was applied to the microscale-patterned electrode. The discharge current and voltage characteristics of the DBD were analyzed under atmospheric conditions. Toluene decomposition rate was evaluated by gas chromatography–mass spectrometry and nondispersive IR-absorption CO2 analysis. A decomposition efficiency of more than 99% was achieved in batch experiments. When the SMD was operated in a flow reactor, 30–80% of toluene was reduced with the percentage depending on residence time. The carbon balance between the toluene starting material and the CO2 product indicates that toluene was almost completely decomposed into CO2 by atomic oxygen in the microplasma.