Study On The Removal Of Trichloroethylene From Water By G-C₃N₄@α-FOD Activated Persulfate Combined With Low Temperature Plasma

Trichloroethylene has been widely used in industry and medicine since the last century.TCE was produced and used on a large scale in the 1970s and 1980s in China.By the beginning of the 21st century,the annual output of TCE could reach 100,000tons,and TCE is widely used as anesthetic,preservative,dry lotion and industrial solvent.TCE is not hydrophilic but is more likely to accumulate at the bottom.So the research on how to effectively remove trichloroethylene has become a hot research topic in recent years.By combining low temperature plasma with persulfate oxidation method,this study explored the optimal parameters of carrier gas flow rate,discharge voltage and initial concentration of low temperature plasma,as well as the optimal parameters of material dosage,initial concentration and persulfate concentration of composite activated persulfate system,and obtained more optimized test parameters through response surface analysis.In this study,the advantages of these two methods were combined and the composite g-C₃N₄@α-FOD was prepared as a catalyst to activate the persulfate system.This study draws the following conclusions:（1）The relationship between the parameters（discharge voltage,initial concentration,carrier gas flow rate）and TCE removal rate was explored when the low temperature plasma treatment alone was used to remove TCE,and it was concluded that the maximum removal rate could reach 74.29%at 480s when DBDP operated alone.The optimal parameters of DBDP running alone are obtained.（2）Firstly,g-C₃N₄@α-FOD was prepared by hydrothermal method and characterized.TCE was then degraded and removed by g-C₃N₄@α-FOD activated persulfate system.It was found that the initial concentration of TCE,the amount of materials added and the concentration of persulfate SPS were closely related to the removal rate of TCE,and the maximum removal rate of 40.01%under the catalytic oxidation system activated by g-C₃N₄@α-FOD was obtained at 480s.It provides a theoretical basis for further advanced treatment of trichloroethylene wastewater.（3）In order to synthesize the advantages of the above two removal methods,the effects of low temperature plasma and g-C₃N₄@α-FOD activated persulfate catalytic oxidation system on the removal of TCE were studied.The collaborative experiment was designed and optimized by response surface optimization analysis.The Box Behnken Design predicted that the optimal TCE removal rate was 95.157%when the initial concentration was 20 mg/L,the discharge voltage was 7kv,the carrier gas flow rate was 14L/h,the material dosage was 60mg,and the SPS concentration was 3.5m M.Under the optimal conditions,the actual removal rate was 93.254±1.25%after three parallel tests,which proved that the experimental value had a good correlation with the predicted value.The possible mechanism of TCE removal under synergistic action was explored.