Abstract:
The increasing discharge of pharmaceuticals and nitrates into aquatic environments poses significant ecological
and public health risks, as conventional wastewater treatment plants often fail to achieve complete removal.
Microbial fuel cells (MFCs) offer a bioelectrochemical approach for simultaneous wastewater treatment and
energy generation; however, their efficiency is constrained by slow electron transfer. This study investigated the
bioelectrochemical degradation of pharmaceuticals and nitrates in wastewater using a dual-chamber MFC
equipped with graphene-coated carbon cloth anodes to enhance microbial electron transfer. Wastewater samples
were collected from a municipal treatment plant and a pharmaceutical discharge site, while electroactive bac
teria enriched from anaerobic sludge served as biocatalysts. Pollutant degradation was analyzed using highperformance liquid chromatography (HPLC) and ion chromatography (IC), and electrochemical performance
was assessed through open-circuit voltage (OCV), power density, cyclic voltammetry (CV), and electrochemical
impedance spectroscopy (EIS). The results demonstrated that graphene-coated anodes enhanced pharmaceutical
degradation from 62.3 % to 87.6 % and nitrate removal from 58.4 % to 83.2 % over 72 hours. Power density
increased by 93.6 % (from 405.6 mW/m2 to 785.3 mW/m2
), while internal resistance decreased by 37.5 %,
indicating improved electron transfer. Biofilm analysis revealed a 55.9 % increase in thickness and a 48.3 %
higher microbial cell density on graphene-coated anodes, with metagenomic sequencing confirming the domi
nance of Geobacter and Shewanella. These findings highlight the potential of graphene-modified MFCs as a sus
tainable and scalable technology for real wastewater treatment.
