Efficient recovery of dissolved Fe(II) from near neutral pH Fenton via microbial electrolysis

Guan Wang, Yufeng Jiang, Kai Tang, Yifeng Zhang*, Henrik Rasmus Andersen

*Corresponding author for this work

Research output: Contribution to journalJournal articleResearchpeer-review

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Abstract

Fe(II) regeneration from ferric sludge via a biocathode and citrate system has recently been proposed to avoid iron-sludge accumulation and iron consumption in homogeneous Fenton treatments. However, poor regeneration rate of Fe(II) from ferric sludge at a near-neutral pH, without an iron-complexing agent, limited its wider practical application. Here, a biocathode augmented with Geobacter sulfurreducens hosted by a microbial electrolysis cell was developed to efficiently regenerate dissolved Fe(II) from ferric sludge at near-neutral pH levels, without using iron-complexing agents. In the Geobacter sulfurreducens-rich biocathode without complexing agents, the regeneration rate of dissolved Fe(II) increased three-fold compared with the biocathode before inoculating Geobacter sulfurreducens. The highest concentration of dissolved Fe(II) increased from 45 mg Fe/L to 199 mg Fe/L at pH 6 when 0.5 V of voltage was applied. Furthermore, 84 mg Fe/L of dissolved Fe(II) was successfully regenerated from ferric sludge during the 123 days' operation of flow-through biocathode. Finally, the regenerated Fe(II) solution without organic matters was successfully applied in a near-neutral pH Fenton treatment to remove recalcitrant pollutants. This Geobacter sulfurreducens-rich biocathode, with its low chemical consumption, high regeneration rate and feasibility for continuous flow operation, offers a more efficient method to realize iron-free in homogeneous Fenton treatments.
Original languageEnglish
Article number129196
JournalJournal of Hazardous Materials
Volume436
Number of pages11
ISSN0304-3894
DOIs
Publication statusPublished - 2022

Keywords

  • Fenton sludge
  • Iron cycle
  • Geobacter
  • Biocathode
  • Recalcitrant pollutants

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