The Study On The Degradation Of Chlorophenol In Auqeous By The Low-temperature Plasma

The wastewater which included chlorophenol compounds is a common wastewater. Chlorophenol compoundshave high toxicity and they are difficult to degradate, therefore, they are easy to accumulate in organism and causing to great threat to organism. Traditional physical, chemical and biochemical methods are difficult to degradate the chlorophenol compounds in wastewater, consequently, many advanced oxidation technologies had been to pay more attention.Low Temperature Plasma wastewater treatment is a new wastewater treatment technology combining high-energy electron irradiation, ozonation and ultraviolet decomposition, meanwhile has the physical and chemical effect. There are hydroxyl radicals generated during the process of Dielectric Barrier Discharge (DBD). Plasma technology has the characteristic of rapid reaction rate,degradation of organism completely and no secondary pollution. Therefore, Low Temperature Plasma Technology has a wide application prospect.At first, we chose 2,4,6-trichlorophenol (2,4,6-TCP) as target degradation pollutants in the experiment and degraded it by low temperature plasma which produced by DBD. We detected the 2,4-dichlorophenol (2,4-DCP) in the solution after the degradation by chloride qualitative test and Mass Spectrometry. Then,2,4-DCP was chose the target degradation pollutant, we studied the effects of different discharge voltage, initial concentration, initial pH and initial conductivity to the degradation of 2,4-DCP. The result shows that the degradation efficiency of 2,4-DCP could reach to 76.13% after thetreatment of 120 min when the initial concentration is 50 mg/L, discharge voltage is 75 V and initial pH is 5.32. We add different catalyst (Fe2+、H2O2、TiO2、I-TiO2) into the 2,4-DCP solution for the purpose of enhancing the degradation of 2,4-DCP, it is because that the number of hydroxyl radicals(·OH) was increased with the presence of catalyst. The degradation efficiency of 2,4-DCP is 83.68% with the presence of TiO2, and then the number can be enchanced to 90.59% after the introduction of 10% I-TiO2. The radical scavenger (tert-butanol,2-propanol) is added into the 2,4-DCP solution to probe the role of ·OH. The pH and TOC of 2,4-DCP solution was decreased with the increasing of discharge time.At last, we characterized the 2,4,6-TCP,2,4-DCP and their degradation products by UV-Vis spectrophotometer and Mass Spectrum, and then analyzed the structure of these degradation products and the degradation path of 2,4-DCP. The experimental results show that 2,4,6-TCP and 2,4-DCP can be degraded effectively by low temperature plasma. This study provided some theoretical guidance for the industrial application of low temperature plasma technology on the treatment of chlorophenol wastewater.