Advanced oxidation coupled with bioelectrocatalysis toward enhanced toluene removal

Area of Science:

• Environmental Science
• Electrochemistry
• Environmental Biotechnology

Background:

• Bioelectrocatalysis shows promise for treating benzene derivative wastewater.
• Limitations include high power use, microbial uncertainty, and free-radical damage.
• Toluene, a common benzene derivative, poses environmental challenges.

Purpose of the Study:

• To develop a novel anode for enhanced toluene removal from wastewater.
• To investigate the mechanisms of bioelectrocatalysis and advanced oxidation in toluene degradation.
• To overcome limitations of existing bioelectrocatalytic methods.

Main Methods:

• A carbon felt (CF) anode modified with sulfurized Fe species (S-ZVI@CF) was synthesized.
• Toluene removal efficiency was tested under varying conditions (pH, sulfate, toluene concentration).
• Microbial community analysis identified key genera involved in biodegradation.
• Advanced oxidation mechanisms involving sulfate and hydroxyl radicals were investigated.

Main Results:

• The S-ZVI@CF anode achieved over 90% toluene removal efficiency at pH 4-8 with specific sulfate and toluene concentrations.
• Biodegradation by the Acinetobacter genus was observed, but incomplete at high toluene concentrations.
• Fe species catalyzed the conversion of sulfate and water into sulfate and hydroxyl radicals, promoting toluene oxidation.
• Post-treatment cleaning and exposure of active Fe species increased total removal to 92.6% at 308 mg L⁻¹ toluene.

Conclusions:

• The S-ZVI@CF anode effectively treats toluene-contaminated wastewater using a combined bioelectrocatalytic and advanced oxidation approach.
• The study highlights the synergistic effects of microbial activity and radical oxidation for pollutant degradation.
• This work offers a new perspective on using advanced oxidation and bioelectrocatalysis for benzene derivative wastewater treatment.