Catalytic Oxidation Of Ethanethiol Using Nonthermal Plasma

In recent years, odors have received increasing attention. Conventional technologies for odors control are incapable of technical and commercial abatement of low concentration malodorants. Nonthermal plasma as a promising technology of polluted gas control has been emerging, however, it still has high cost problem. So, this study is to develop a hybrid process of plasma and catalysis through adding catalysts in the reactor to strengthen plasma chemistry processing for meeting high cost.Firstly, the effects of three various types of discharges such as pulsed corona discharge, dielectric barrier discharge and hybrid discharge (corona and dielectric barrier discharge occurring together) were investigated. Then, humidity in air, pulse repetition, initial concentration of ethanethiol, flow rate, peak voltage on removal performance was investigated. Last, catalytic oxidation of ethanethiol using Mn/γ-Al₂O₃, Cu/γ-Al₂O₃, Fe/γ-Al₂O₃, Mn-Fe/γ-Al₂O₃, Cu-Mn/γ-Al₂O₃ and corresponding energy efficiency were also examined.The results were as follows:The ethanethiol removal rate increased with energy density but energy efficiency was first increased and then decreased with energy density under three various types of discharges. It can be concluded that pulsed corona discharge required the lowest energy density under the similar removal performance.The ethanethiol removal and energy efficiency of dielectric barrier discharge first increased and then decreased as humidity in air increased at the low energy density, which was different from the case at the high energy density that it all time decreased with increasing humidity in air. The ethanethiol removal and energy efficiency of corona discharge was increased with pulse repetition. The higher the pulse repetition was, the higher temperature was observed in the reactor and more energy was consumed. Besides, considering other parameters, the removal rate of corona discharge increased with increasing peak voltage and decreasing initial concentration and flow rate, while at the same time, energy efficiency first increased and then decreased with increasing peak voltage and increased with increasing initial concentration and flow rate. When using corona discharge with catalysts, ethanethiol removal rate and energy efficiency were improved evidently. Mn-Fe/γ-Al₂O₃ had the best removal rate and maximum energy efficiency was 200g/kWh at 2.5J/L. The mechanism of ethanethiol oxidation is possibly (a) ethanethiol is decomposed and oxidized by energized electrons and activated oxygen atoms in the discharge zone; (b) ethanethiol is further decomposed and oxidized by ozone and oxygen species on different catalysts to intermediates.