酸性体系中Pd／PPy／foam-Ni电极电化学还原三氯甲烷

Electrochemically Reductive Dechlorination of Chloroform by Palladium/Polymeric Pyrrole Film/Foam-Nickel Composite Electrode in Acidic System

在沉积电流密度5mA.cm-2,沉积时间40min条件下,通过电沉积方法制备Pd/PPy/泡沫镍(foam-Ni)电极,以Pd/PPy/foam-Ni电极为阴极研究酸性体系中三氯甲烷的电化学还原脱氯,实验在室温条件下进行.采用循环伏安法对电极进行测试,Pd/PPy/foam-Ni电极在-500mV(vsHg/Hg2SO4)左右获得很大的氢吸附峰电流值,峰电流值为-100mA.扫描电镜(SEM)分析表明,聚吡咯的引入改变了Pd在电极表面的沉积形态,使电极表面具有很好的空间延伸性.在酸性体系中进行Pd/PPy/foam-Ni电极对三氯甲烷的电化学还原脱氯实验,结果表明,综合考虑三氯甲烷去除率及脱氯过程电流效率,在保证脱氯过程电流效率为44.17%的条件下,三氯甲烷的去除率为49.23%,此时最佳脱氯电流密度为0.05mA.cm-2,最佳脱氯时间为180min,实现了在酸性水溶液体系中,低初始浓度三氯甲烷较好的脱氯效果.

Palladium/polymeric pyrrole film/foam-nickel （Pd/PPy/foam-Ni） composite electrode were prepared by the electrodeposition method with the electrodepositing current density of 5 mA. cm- 2 and the electrodepositing time of 40 min. Electrochemical reductive dechlorination of chloroform in acidic system was investigated using the Pd/PPy/foam-Ni electrode at ambient temperature. The electrochemical deposition behaviors of Pd/PPy/foam-Ni electrode were studied by means of cyclic voltammetry （CV）. Cyclic voltammetry results reveal that the large hydrogen adsorption peak current of - 100 mA on Pd/PPy/foam-Ni electrode was obtained at about -500 mV （vs Hg/Hg2SO4 ）. SEM micrographs show that the addition of polymeric pyrrole changed the distributing configuration of Pd microparticles on the electrode and Pd/PPy/ foam-Ni electrode possessed a good spatial extension. Chloroform dechlorination experimentes were conducted in acid system. Dechlorination experimental resuhs indicate that, with the integrated analysis of removal efficiency and current efficiency, with the high current efficiency of 44.17%, the removal efficiency of chloroform on Pd/PPy/foam-Ni electrode was 49.23% ,under the optimum conditions of the dechlorination current density of 0.05 mA·cm^-2 and the dechlorination time of 180 min. In acid aqueous solution, with low initial concentration of chloroform, the results of dechlorination experiment were preferable.