Pd修饰Ti电极对水相中2,4,5-PCB还原脱氯的研究

实验研究了Pd修饰Ti电极对甲醇/水相中十六烷基三甲基溴化铵(CTAB)增溶的2,4,5-PCB(PCB: 多氯联苯)的电化学还原脱氯作用. 采用两室流通式电解池, 考察了Pd负载量、电极结构、电场条件和溶液流速对2,4,5-PCB的去除效率的影响. 优化条件是: Pd负载量为3 mg•cm-2, 阴极为3层电极极板, 电极电位为－1.10 V(vs SCE); 溶液流速对脱氯效率的影响不明显. 在该条件下经过9 h电解, 2,4,5-PCB的去除率达96.2%, 脱氯产物未完全生成联苯, 其产率为89.6%, 电流效率介于11.3%~33.0%之间.

Electrocatalytic Reductive Dechlorination of 2,4,5-PCB in Aqueous Solution by Palladium-modified Titanium Mesh as Cathode

Electrocatalytic reductive dechlorination of 2,4,5-PCB(PCB:polychlorinated biphenyls) in aqueous solution containing methanol and hexadecyltrimethyl ammonium bromide (CTAB) was studied in a Teflon-made two-compartment flow-through cell with a palladium-loaded permeable titanium mini mesh cathode and a platinum foil anode. The experiments were carried out to explore the effects of palladium loading, electrode structure, applied cathode potential and catholyte flow rate on dechlorination. The results indicated that the optimal conditions were 3 mg Pd loading /cm2 geometric area, three-layer cathode and -1.10 V (vs SCE) controlled potential. After 9 h electrocatalytic reduction under the optimal conditions, the dechlorination rate of 2,4,5-PCB reached 96.2%, but the conversion rate to biphenyl was 89.6%. The current efficiency changed between 11.3% and 33.0% during the electrocatalytic reduction.