Degradation Of CH₃SH By Corona Discharge Plasma Coupled With Photocatalysis

With the rapid development of industry,the industrial exhaust gas emission standards are more and more strict in China,the degradation of sulfur-containing malodorous gases has also received increasing attention,especially,CH₃SH is a typical organic sulfur-containing malodorous gas pollutant.If CH₃SH is directly discharged in the atmosphere without any treatment,which could not only damage human health,but also cause environmental problems such as acid deposition,photochemical smog,and haze.The phenomenon destroys ecological environment and hinders the sustainable development of human beings.Non-thermal plasma technology has been widely studied and applied in the treatment of low-concentration pollution gas,which is a research hotspot in recent years.Non-thermal plasma technology has the advantages of rapid and thorough reaction to the degradation of malodorous gases,and can completely degrade gaseous pollutants in a short time.However,the use of this technology alone has the disadvantage of high energy consumption and high ozone concentration at the outlet.Photocatalytic technology has certain advantages in the removal of gaseous pollutants with higher concentration,but it has the disadvantages,such as longer time for treating the gaseous pollutants and incomplete degradation in the treatment of complex organic gaseous pollutants.The synergistic use of the two technologies,which combines the high reactivity of the non-thermal plasma and the high reaction selectivity of the photocatalyst.It not only improves the degradation efficiency of CH₃SH,reduces the formation of harmful by-products such as SO₂ and O₃,but also increases the selectivity of CO₂.And the synergy reduces the energy consumption.The degradation of CH₃SH was studied in this paper by the linear-cylindrical DC corona discharge plasma technology cooperating with four photocatalysts?TiO₂?Ag/TiO₂?Mn/TiO₂ and Ag-Mn/TiO₂?.The effects of different inlet concentration,oxygen concentration and relative humidity on the CH₃SH conversion and energy yield by DC corona discharge plasma alone and photocatalysis alone were studied.In view of the high energy consumption of CH₃SH degradation,high O₃ content of export,low CO₂ selectivity by DC corona discharge plasma technology alone and the low degradation efficiency of CH₃SH,long reaction time and complicated products by photocatalytic technology alone,conversion of CH₃SH and production of export products were investigated by DC corona discharge plasma technology cooperating with photocatalytic technology.It was found that the presence of photocatalysts improved the conversion rate and energy yield of CH₃SH,and reduced the outlet concentration of CO,SO₂ and O₃,and also improved the selectivity of CO₂.The experimental results show that DC corona discharge plasma with photocatalysis has more advantageous in the degradation of CH₃SH than the respective effects.In this paper,the process and mechanism of corona discharge plasma coupled with photocatalysis for CH₃SH degradation were discussed with the analysis of inlet and outlet gas by FT-IR and sulfur element deposition on the photocatalyst surface by X-ray photoelectron spectroscopy.