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

Electrocatalytic reductive dechlorination of 2,4,5-PCB 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 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 electrocatalytic reduction.