Cathode potential regulation in a coupled bioelectrode-anaerobic sludge system for effective dechlorination of 2,4-dichloronitrobenzene.

•Cathode potential is an essential control parameter in bioelectrochemical system.•MES-UASB coupled reactor achieved an enhancement for transformation of 2,4-DClNB.•Lower cathode potential favored the breakage of C-Cl bond and promoted the dechlorination reaction.•Dechlorination functional microbes were enriched at low cathode potential in MES-UASB system.