Highly efficient nitrobenzene removal by coupling electrochemical filtration with a microbial electrolysis cell

Conventional microbial electrolysis cell (MEC) for treating nitrobenzene (NB) suffers from insufficient mass transfer, leading to low removal efficiency. Electrochemical filtration (EF) was coupled with MEC to construct an EF-MEC system, which increased the removal rate of NB by 6.5 times in comparison with a conventional MEC. The EF process enhanced the convection mass transfer of NB and hence increased its removal. The EF process was also accompanied by a lower loading rate of NB so that 88.1% of NB in the feed could be reduced and the conversion ratio of NB to AN was high up to 98.2%. Therefore, the toxic effects on anode biofilms were relieved, leading to the enrichment of electroactive microorganisms, especially Geobacter, Desulfovibrio, and Rhodop-seudomonas. The enriched anode electroactive microorganisms reciprocally promoted electrogenesis and hence the removal of NB. This EF-MEC system has functionally complemented the benefits between the EF and MEC processes, and it is very promising in treating NB-contained wastewater.