电解对氯苯酚稀水溶液中脱氯降解机理研究

利用石墨电极进行了多种条件下对氯苯酚水溶液的电解研究。研究结果表明,CODCr去除率和脱氯率随电压的升高呈先升高后下降的趋势、随对氯苯酚质量浓度的升高呈指数下降、随溶液pH的升高而升高。碱性条件下电解效果明显优于中性和酸性条件。在电压为10V,pH≈12,电解100mg L的对氯苯酚溶液2h后,CODCr去除率可达52 94%,脱氯率达52 8%。由脉冲辐解瞬态吸收光谱可知,中性、酸性条件下降解机制均为OH·自由基的作用,经过瞬态分子OH-adducts(OH加合物)的中间产物进一步氧化降解;碱性条件下通过OH·自由基和对氯苯酚氧基负离子的阳极直接失电子氧化作用2种降解机制,经过瞬态分子氯代酚氧自由基中间产物氧化降解对氯苯酚,产物分析结果显示生成了对苯二酚和苯醌等中间产物。 

The Research on the Mechanism of Electrochemical Dechlorination of 4-Chlorophenol

The electrochemical process of 4-chlorophenol with graphite rods electrodes under different conditions was studied.The result shows that CODCr degradation rate and dechlorination rate first ascend and then descend with the increase of voltage;exponentially decay with the increase of mass concentration of 4-chlorophenol;and increase with the rise of pH.Alkaline condition is preferred to neutral and acidic conditions in the results of degradation.A solution of 100 mg/L 4-chlorophenol (pH≈12) was electrolyzed at a constant potential of 10 V for 2 hours and the CODCr degradation rate is 52.94% and dechlorination rate is 52.8%.By means of the high energy pulse electron beam produced by a linear accelerator as well as a set of transient absorption spectra recorder,the reaction mechanism of 4-chlorophenol was found to be the function of reactive particles OH·. The intermediate product is OH-adducts under neutral and acidic conditions,while 4-chlorophenol is degraded by both action of OH· and direct oxidation on anode under alkaline condition.Analysis of products shows that the intermediate products are hydroquinone and benzoquinone.