Research On Removal Of Trichloroethylene And Dichloromethane By Rotating Electrode Discharge Reactor

As one kind of the main precursors of PM2.5 and photochemical pollution,chlorine containing volatile organic compounds?CVOCs?are difficult to degrade naturally in the environment,and easy to accumulate in the organism,which may have the risk of carcinogenesis,teratogenesis and mutation to human body.In this study,a rotating electrode discharge plasma reactor was devised to remove these pollutants.The inner diameter of the main glass cylinder of the reactor is 5 cm.A stainless steel electrode screw driven by the motor is fixed in the center of the cylinder as the discharge anode.A layer of aluminum foil film is attached to the cylinder wall as the grounding cathode.In the middle of the electrode,there are three 3cm long small screw rods which are 60°to each other.The distance between the small screw rods and aluminum foil is 1 cm.By studying the discharge characteristics and power under different speed and voltage,the advantages of the reactor are summarized:large reaction space,reducing short circuit and overheat,stable discharge and low energy consumption.In this research,trichloroethylene and dichloromethane,the common chlorinated organic pollutants in the field of industrial cleaning,are taken as the typical representatives of unsaturated and saturated CVOCs.The general rule of CVOCs treatment is obtained by studying the two substances.In this study,the influence of key parameters?peak electric pressure,rotation speed,initial concentration,gas flow,oxygen concentration?on the removal effect is specifically studied,The energy efficiency in the degradation process was calculated,and the reason of its change was analyzed systematically.Under optimized conditions,the removal efficiency of trichloroethylene and dichloromethane can reach 93.2%and 46.3%respectively,and the energy yield can reach 4.93 g/k Wh and 2.50 g/k Wh respectively.Meanwhile,the degradation mechanism of trichloroethylene and dichloromethane in aerobic and anaerobic environments is also studied.Due to the similar properties of the two substances and elements,the gas phase products are similar.In the anaerobic environment,the main gas phase products are HCl and Cl₂.In the aerobic environment,the main gas phase products are CO₂,H₂O and Cl₂,and the by-products are COCl₂ and O₃.Finally,the feasibility of industrial application of plasma technology is discussed by comparing plasma technology with typical VOCs purification process.