Removal and fate of trace organic compounds in microbial fuel cells

• Removal of 26 TOrCs was investigated in single chamber and double chamber MFCs.
• Removal processes involve sorption of TOrCs to carbon electrodes and biodegradation.
• Removal of nonionic TOrCs is determined by biodegradability and hydrophobicity.
• Electrostatic interactions play an additional role for removal of charged TOrCs.

This study focused on understanding and characterizing the removal of trace organic compounds (TOrCs) in microbial fuel cells (MFC). 26 TOrCs with broad physicochemical properties were spiked in synthetic wastewater. Single-chamber air-cathode MFC (SMFC) and double-chamber air-cathode MFC (DMFC) were constructed to provide combined or separated oxidation/reduction environments for TOrCs removal. The study showed that TOrCs removal processes involved both sorption and biodegradation. For neutral TOrCs, the removal efficiency was affected primarily by the biodegradability probability and hydrophobicity of the compounds, while electrostatic interactions played an additional role in the MFCs as the removal of positively charged TOrCs was generally higher than negatively charged TOrCs. The presence of TOrCs showed negligible impact on MFC power generation, likewise the operation of MFCs had marginal effect on TOrCs removal, except longer residence time in MFCs improved biological removal performance.

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