Conductive Materials on Biocathodes Altered the Electron-Transfer Paths and Modulated γ-HCH Dechlorination and CH4 Production in Microbial Electrochemical Systems

Jie Cheng, Meng Liu, Xin Su, Bruce E. Rittmann, Zhijiang Lu, Jianming Xu, Yan He

Research output: Contribution to journalArticlepeer-review

7 Scopus citations

Abstract

Adding conductive materials to the cathode of a microbial electrochemical system (MES) can alter the route of interspecies electron transfer and the kinetics of reduction reactions. We tested reductive dechlorination of γ-hexachlorocyclohexane (γ-HCH), along with CH4 production, in MES systems whose cathodes were coated with conductive magnetite nanoparticles (NaFe), biochar (BC), magnetic biochar (FeBC), or anti-conductive silica biochar (SiBC). Coating with NaFe enriched electroactive microorganisms, boosted electro-bioreduction, and accelerated γ-HCH dechlorination and CH4 production. In contrast, BC only accelerated dechlorination, while FeBC only accelerated methanogenesis, because of their assemblies of functional taxa that selectively transferred electrons to those electron sinks. SiBC, which decreased electro-bioreduction, yielded the highest CH4 production and increased methanogens and the mcrA gene. This study provides a strategy to selectively control the distribution of electrons between reductive dechlorination and methanogenesis by adding conductive or anti-conductive materials to the MES’s cathode. If the goal is to maximize dechlorination and minimize methane generation, then BC is the optimal conductive material. If the goal is to accelerate electro-bioreduction, then the best addition is NaFe. If the goal is to increase the rate of methanogenesis, adding anti-conductive SiBC is the best.

Original languageEnglish (US)
Pages (from-to)2739-2748
Number of pages10
JournalEnvironmental Science and Technology
Volume57
Issue number7
DOIs
StatePublished - Feb 21 2023

Keywords

  • biochar
  • electro-bioreduction
  • magnetite nanoparticles
  • methane
  • γ-hexachlorocyclohexane

ASJC Scopus subject areas

  • General Chemistry
  • Environmental Chemistry

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