Stimulative mineralization of p-fluoronitrobenzene in biocathode microbial electrolysis cell with an oxygen-limited environment

• Oxygen-limited oxidation environment most beneficial for p-FNB treatment.
• Integrated reduction and oxidation mechanism applicable in the biocathode.
• A prior hydrolyzed dehalogenation pathway was achieved for mineralization of p-FNB.

p-Fluoronitrobenzene (p-FNB) is a toxic compound and tends to accumulate in the environment. p-FNB can be effectively removed and defluorinated in a single-chamber bioelectrochemical system (BES). To verify the suppositionally integrated reductive and oxidative metabolism mechanism in the BES, an oxygen-limited environment was used, with pure oxygen and nitrogen environments used as two controls. Under the oxygen-limited condition, the most excellent performance was achieved. The defluorination rate and mineralization efficiency were 0.0132 h−1 and 72.99 ± 5.68% after 96 h, with 75.4% of fluorine in the form of the fluoride ion. This resulted from the unique environment that allowed conventionally integrated reductive and oxidative catabolism. Moreover, the oxidation–reduction potential (ORP) had a significant effect on microbial communities, which was also an important reason for performance diversity. These results provide a new method for complete p-FNB treatment and a control strategy by ORP regulation for optimal system performance.