Decomposition of gas-phase chloroform using nanophotocatalyst downstream the novel non-thermal plasma reactor: by-products elimination

Abstract

Combination the non-thermal plasma technique by photocatalytic oxidation can enhance volatile organic compounds degradation. In this study, the decomposition of chloroform vapors in a novel non-thermal plasma reactor as well as an integrated system of this reactor in conjunction with the photocatalysis process was investigated. Expanded graphite was used as discharge electrode of dielectric barrier discharge reactor and the support of TiO2 and ZnO catalysts as well. Results showed that chloroform degradation increased in hybrid system. The non-thermal plasma reactor had high content of NO and NO2, whereas the concentration of these two pollutants dropped dramatically in hybrid system; moreover, the generated ozone from the non-thermal plasma process was degraded on the photocatalyst and consequently was not detected in the output gas of the combined system. The generated organic by-products in non-thermal plasma process (phosgene and trichloroacetaldehyde) were reoxidized with un-oxidized chloroform in the second stage of the combined system. This increased the selectivity of CO2 and Cl2.