Current generation in microbial electrolysis cells based on an abiotic anode and planktonic Geobacter sulfurreducens in the presence of suspended reduced graphene oxide and activated carbon

This study investigates the effect of activated carbon (AC) and reduced graphene oxide (rGO) nanoparticles on the electrochemical performance of microbial electrochemical cells (MECs) utilizing an abiotic anode and planktonic Geobacter sulfurreducens. MEC without bacteria showed a linear correlation between nanoparticle concentration and current density. MEC with 1 mg/mL rGO nanoparticles and planktonic G. sulfurreducens exhibited a rise in current density, peaking at 2.52 A/m², whereas with AC, it remained stable at about 1.85 A/m². The control without nanoparticles showed 0.63 A/m². Electrochemical impedance spectroscopy revealed a decrease in solution resistance (Rs) and charge transfer resistance (Rct) with AC, and rGO. COD removal was highest in the AC system, 32 ± 0.03 %; followed by rGO, 20 ± 0.5 %; and in the control, 18 ± 5.2 %. Raman spectroscopy revealed changes in the carbon structure of nanoparticles due to bacterial attachment. The findings confirm that the addition of AC, and rGO enhances electrochemical performance and bacterial viability.