External potential regulated biocathode for enhanced removal of gaseous chlorobenzene in bioelectrchemical system. (July 2021)

• Record Type: Journal Article
• Authors: Ying, Zanyun; Chen, Han; Gao, Jialing; Zhang, Shihan; Peng, Ruijian; You, Juping; Chen, Jianmeng; Zhao, Jingkai
• Is Part Of: Chemosphere. Volume 274(2021)
• Publication Date: 2021-07
• Subjects: Biocathode -- Potential regulation -- Gaseous chlorobenzene -- Microbial community structure -- Degradation pathway; Pollution -- Periodicals; Pollution -- Physiological effect -- Periodicals; Environmental sciences -- Periodicals; Atmospheric chemistry -- Periodicals; 551.511
• DOI: 10.1016/j.chemosphere.2021.129990
• Languages: English
• ISSNs: 0045-6535

Abstract

Abstract: Microbial electrolysis cell (MEC) with a biocathode could provide extra reaction driving force for gaseous chlorobenzene (CB) removal. In this work, external potentials (−0.1 to −0.7 V vs. SHE) were applied to regulate the biocathodic activity. Results showed −0.3 V was the optimum potential, while the removal efficiency, dechlorination efficiency and Coulombic efficiency achieved 94%, 65%, and 89%, respectively. Electrochemical stimulation enriched dechlorination microorganisms ( Achromobacter and Gordonia ), and significantly improved CB mineralization efficiency, which was twice higher than that without additional potential at 300 mg m −3 inlet concentration. Furthermore, electron transfer between biocathode and microorganisms was mainly through direct electron transfer (DET). A new integrated redox pathway for CB anaerobic degradation was proposed, in which CB was sequentially converted into 2-chlorophenol and 3-chlorocatechol, then dechlorinated to catechol, and finally mineralized into CO2 . Overall, this work provided an insight into gaseous CB bioelectrochemical degradation through the potential regulation. Graphical abstract: Image 1 Highlights: Regulated biocathode potential facilitated gaseous CB mineralization and dechlorination. The optimal performance of MEC was achieved at the potential of −0.3 V vs. SHE. Direct electron transfer was the main electron transfer pathway between electrode and microorganisms. A new CB anaerobic degradation pathway in MEC was proposed.