Benzene transformation in two dielectric barrier discharge reactors having special arrangement

Argon-benzene (Ar-Bz) gas phase plasma chemistry work is explored for benzene transformation employing the dielectric barrier discharge (DBD) cold plasma technique. To do so, experiments are carried out with two identical coaxial DBD reactors in serial-type arrangements. The first carries moist Ar having 100% relative humidity (90% of total Ar flowing over water) and its outlet is mixed with Bz, which is saturated in the remaining 10% Ar at the inlet of the second reactor before plasma generation. This type of arrangement perhaps favors Bz transformation significantly for explicit products because the H-2 generated in the first reactor as one of the major in situ products in the Ar-moisture DBD system might facilitate chemical reduction of Bz to biphenyl in the second reactor during DBD. Conversely, H2O2, another product in Ar-moisture discharge, enhances the yields of phenol. DBD outlet products, such as methane and leftover Bz, are analyzed and estimated with online gas chromatograph-flame ionization detector analysis, whereas H-2 is analyzed with gas chromatograph-thermal conductivity detector. Additionally, the offline gas chromatograph-mass spectrometer analysis of acetone solutions of surface deposits obtained after discharge reveals the formation of phenol and biphenyl along with other products. The periodically analyzed data reveal that the generation of phenol, biphenyl, and CH4 relate directly to discharge duration and input moisture concentration.