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Synergic degradation of 2,4,6-trichlorophenol in microbial fuel cells with intimately coupled photocatalytic-electrogenic anode

Author:
Wang, Xiaoxuan, Hu, Jingping, Chen, Qin, Zhang, Peng, Wu, Longsheng, Li, Jianfeng, Liu, Bingchuan, Xiao, Keke, Liang, Sha, Huang, Long, Hou, Huijie, Yang, Jiakuan
Source:
Water research 2019 v.156 pp. 125-135
ISSN:
0043-1354
Subject:
2,4,6-trichlorophenol, Geobacter, Pseudomonas, bioaccumulation, bioanodes, biofilm, carbon, chlorine, coatings, microbial communities, microbial fuel cells, phenol, photocatalysis, pollutants, sewage, toxicity, wastewater treatment
Abstract:
A microbial fuel cell system with intimately coupled photocatalytic-electrogenic anode (photocatalytic-MFC) was proposed for the synergetic degradation of 2,4,6-trichlorophenol (2,4,6-TCP) which has a structure of three chlorine groups connecting to a phenol ring and is well recognized as a recalcitrant pollutant for its high toxicity, bioaccumulation and persistence. The photocatalytic-electrogenic anode was prepared by coating mpg-C3N4 on a carbon felt anode, followed by inoculating with municipal sewage and acclimating with 2,4,6-TCP at gradient concentrations. Improved TCP degradation was achieved, showing 79.3% of TCP removal in 10 h with an original concentration of 200 mg L−1, which was higher than that obtained with the unilluminated MFC (66.0%) and the photocatalytic-only process (56.1%). The coupled photocatalytic-electrogenic process demonstrated different degradation pathways compared with the photocatalytic-only process, with one open-chain compound (2-chloro-4-keto-2-hexenedioic acid, 2-CMA) detected in the photocatalytic-MFC system. Microbial community analysis revealed that Pseudomonas, instead of Geobacter observed in the unilluminated MFC bioanode, dominated in the photocatalytic-electrogenic anode MFC biofilm, which might be responsible for enhanced current generation in the coupled system. In addition, biofilm rich with Rhodococcus on air-cathode was also responsible for the enhanced TCP removal. This research provides an efficient strategy for the treatment of wastewater with recalcitrant contaminants by intimate-coupling of the photocatalytic and the electrogenic processes.
Agid:
6345608