Generation, utilization, and transformation of cathode electrons for bioreduction of Fe(III)EDTA in a biofilm electrode reactor related to NOx removal from flue gas

Wei Li, Yinfeng Xia, Jingkai Zhao, Nan Liu, Sujing Li, Shihan Zhang

Research output: Contribution to journalArticlepeer-review

Abstract

A chemical absorption-biological reduction (CABR) integrated system, which employs iron chelate as a solvent, is under development for NOx removal from flue gas. Biofilm electrode reactor (BER) is deemed as a promising bioreactor to regenerate the iron chelate. Although it has been proved that BER can significantly enhance the bioreduction of Fe(III)EDTA, the bioelectrochemistry mechanism involved in the bioreduction of Fe(III)EDTA remains unknown. This work aims to explore this mechanism via the analysis of the generation, utilization, and transformation of cathode electrons in the BER. The results indicate that the generation of cathode electrons follows Faradays law. The generated cathode electrons were used to produce H2 and directly reduce Fe(III)EDTA in the BER. Meanwhile, the produced H2 served as an electron donor for bioreduction of Fe(III)EDTA. The excess H2 product was transformed to simple organics, e.g., methanol by the hydrogen autotrophy of Pseudomonas under the inorganic and anaerobic conditions. Overall, this work revealed that the reduction of Fe(III)EDTA in the BER was enhanced by both direct electrochemical reduction and indirect bioreduction using H2 as an intermediate. It is also interesting that the excess H2 product was transformed to methanol for microbial metabolism and energy storage in the BER.

Original languageEnglish (US)
Pages (from-to)4530-4535
Number of pages6
JournalEnvironmental Science and Technology
Volume49
Issue number7
DOIs
StatePublished - Apr 7 2015
Externally publishedYes

ASJC Scopus subject areas

  • General Chemistry
  • Environmental Chemistry

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