Degradation of p-nitrophenol by coupled cathodic reduction and anodic oxidation in a self-powered bioelectrochemical system and analysis of microbial community

Abstract

Cost-effective treatments of recalcitrant pollutants in wastewaters are required. The coupling degradation of p-nitrophenol (PNP) reduction in cathode and p-aminophenol (PAP, reduction product of PNP) oxidation in anode was studied in a bioelectrochemical system (BES) solely catalyzed by bacteria consortia, with no power input. In the cathode chamber, 50 mg L⁻¹ PNP was reduced by 96.2 ± 2.4% within 96 h. PNP reduction efficiency was notably improved than that (63.8 ± 2.6%) in the abiotic cathode control. In the anode chamber, 20 mg L⁻¹ PAP was removed by 94.0 ± 0.6% within 30 h. The reduction and oxidation peaks in cyclic voltammetry curves of the cathode and anode verified the coupled degradation process. Illumina Mi-seq sequencing revealed similar predominant bacteria with different percentages on the cathode and anode. The bacteria composition was more diverse on the anode. At the phylum level, higher prevalence of Chlorobi, Bacteroidetes, Thermi and Actinobacteria on the cathode than that on the anode were discovered. Meanwhile, Thiobacillus, Methanomethylovorans, Sphingobium and Geobacter were superior on the anode than the cathode at the genus level. Coupling treatment of PNP reduction in cathode and PAP oxidation in anode was realized in a bio-catalyzed BES. Enhanced degradation in a self-powered BES is an economical and efficient strategy for the treatment of nitroaromatic pollutants.

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Identifiers

DOI

10.5004/dwt.2018.22947

Journal

Desalination and Water Treatment

Year

2018