Biocatalysed sulphate removal in a BES cathode

Area of Science:

• Environmental science
• Electrochemistry
• Microbiology

Background:

• Sulphate reduction is a key process in anaerobic environments.
• Biological cathodes in bioelectrochemical systems offer potential for pollutant removal.
• Understanding sulphate reduction mechanisms in these systems is crucial for their application.

Purpose of the Study:

• To investigate sulphate reduction in a biocathode separate from organic matter oxidation.
• To determine the required conditions and energy input for biological sulphate reduction.
• To assess the fate of produced sulphide under high biocathode pH.

Main Methods:

• Operation of a bioelectrochemical system as a microbial fuel cell and microbial electrolysis cell.
• Controlled manipulation of applied voltage and cathodic potential.
• Monitoring of sulphate reduction and sulphide production at high biocathode pH (10).

Main Results:

• Sulphate reduction was not observed without applied voltage.
• Reduction initiated at a cathodic potential of -0.26V vs. SHE, with a minimum energy requirement of 0.7V.
• Maximum sulphate removal was achieved at 1.4V applied, producing entrapped ionic sulphide due to high pH.

Conclusions:

• Applied voltage is essential for sulphate reduction in this biocathode setup.
• The system demonstrates effective sulphate removal and sulphide containment.
• This approach holds promise for treating sulphate-rich wastewater in bioelectrochemical systems.