阴极电催化还原降解水中三氯乙烯实验研究

三氯乙烯是地下饮用水中的主要有机污染物之一,广泛应用于金属加工、电子和干洗等行业,由于其土壤吸附性弱、水溶性低,所以很容易在地下水中积累,严重影响人体健康。文章利用独立设计的电化学双室反应装置,进行了阴极电催化还原法降解水中三氯乙烯的实验,并选择了检测降解产物较好的DB-VRX色谱柱,探讨了不同电极电势、电子供体及用量对三氯乙烯降解效果的影响,获得了水相体系中降解三氯乙烯的最佳实验条件。当采用DB-VRX色谱柱,固定阴极电势-0.45V(vs.NHE),电子供体为甲酸0.4 g/L,三氯乙烯初始浓度约为10 mg/L时,经过44 h反应,三氯乙烯的降解率达到了58.2%,并生成二氯甲烷、三氯甲烷等产物。通过GC-MSD对降解产物进行分析,提出了阴极电催化还原降解水中三氯乙烯的机理。

Experimental Study on Electrolytic Dechlorination of Trichloroethene in Water at Cathode

Trichloroethene(TCE)as one of major organic pollutants in drinking water is seriously harmful to human health due to its weak soil adsorption and limited water solubility.It is easily accumulated in underground water.Electrolytic dechlorination of TCE in water at cathode using an independent design of electrochemical experimental equipment was introduced.A better chromatographic column was chosen.Effects of electrode potential,electron donor and its dosage on TEC degradation rate were discussed.The optimum experimental conditions in water system was obtained based on series trials,with the column as DB-VRX,under the best experimental conditions of cathode potential-0.45 V(vs.NHE),formic acid as electron donor with concentration of 0.4 g/L,initial concentration of TCE 10 mg/L approximately,TCE was degraded by 58.2% after 44 h.Methylene chloride and chloroform were found during the experiment.The degradation mechanisms were discussed based on the analysis of degradation products.