Enhanced tetracycline removal by bioelectro-Fenton through boosting Fe2+/Fe3+ cycle from microbial iron conversion

Critical Review on the Mechanisms of Fe2+ Regeneration in the Electro-Fenton Process: Fundamentals and Boosting Strategies

“…148,149 As such, Fe 2+ regeneration mainly depends on the cathodic Fe 3+ reduction, following the mechanisms that have been described throughout the text. The efficiency of such iron reduction powered by the harvested bioelectrons has been demonstrated using Shewanella decolorationis S12, 150 Shewanella putrefaciens SP200, 151 Pseudo-monas, 152 and mixed bacterial cultures from sludge. 153−155 Recently, a novel bio-EF system (Figure 13b) was proposed, in which Fe 2+ mainly converted by Pseudomonas and Geobacter at the anode chamber was transported into the cathodic part via the cation exchange membrane for Fenton's reaction 2.…”

“…153−155 Recently, a novel bio-EF system (Figure 13b) was proposed, in which Fe 2+ mainly converted by Pseudomonas and Geobacter at the anode chamber was transported into the cathodic part via the cation exchange membrane for Fenton's reaction 2. 152 However, the low current output from the bio-EF process is still a concern for quantitative cathodic iron reduction. 156 Because of the oxidative environment generated in the EF half-cell of bio-EF systems, it is preferable to keep microorganisms in the anodic half-cell.…”

“…Such systems have been systematically described in recent review papers. , In bio-EF systems, microbial cultures are not directly involved in the degradation of pollutants on the cathodic chamber because the microorganisms are isolated in the anodic compartment. , As such, Fe 2+ regeneration mainly depends on the cathodic Fe 3+ reduction, following the mechanisms that have been described throughout the text. The efficiency of such iron reduction powered by the harvested bioelectrons has been demonstrated using Shewanella decolorationis S12 , Shewanella putrefaciens SP200 , Pseudomonas, and mixed bacterial cultures from sludge. − Recently, a novel bio-EF system (Figure b) was proposed, in which Fe 2+ mainly converted by Pseudomonas and Geobacter at the anode chamber was transported into the cathodic part via the cation exchange membrane for Fenton’s reaction . However, the low current output from the bio-EF process is still a concern for quantitative cathodic iron reduction .…”

“…(b) A novel double-chamber bio-EF with iron transported between anode and cathode chambers. Reproduced with permission from ref . Copyright 2022 Elsevier.…”

Iron Oxide Anchored on Porous Carbon Derived from Metal–Organic Frameworks as an Efficient Catalyst toward In Situ Generation of H2O2 and a Hydroxyl Radical for Methylene Blue Degradation in Microbial Fuel Cells

“…Depending on how and where H 2 O 2 is generated, electro-Fenton systems coupled with MFC can be classified into in situ coupled systems and heterogeneous coupled systems. , The H 2 O 2 production and in situ utilization are still the challenges of the MFC-EF system. A bioelectro-Fenton (BEF) cathode chamber can effectively mineralize difficult-to-degrade organic compounds, such as dyes, antibiotics, p -nitrophenols, estrogens, etc. − A dual-chamber MFC in situ, which produces H 2 O 2 has been developed by Zhu et al An external iron source was used to produce hydroxyl radicals, which were capable of degrading nitrobenzol with an efficiency of 100% for nitrobenzol removal and 85% for total organic carbon (TOC) removal, respectively. The maximum amount of H 2 O 2 generated in situ using a Fe@Fe 2 O 3 /graphite felt composite cathode in MFC was 135.96 μmol/L, and the degradation efficiency of triphenyltin chloride (TPTC) reached 78.32 ± 2.07% by Yong et al Feng et al treated wastewater at neutral pH with the BEF process, which achieved complete decolorization and mineralization of orange-yellow II at neutral pH and a maximum power of 230 mW/m 2 .…”