Impact of anode surface modifications on microbial fuel cell performance and algal biomass production

In this study, the performance of dual-chamber microbial fuel cells with carbon fiber (CF) anodes surface modified by multi-walled carbon nanotube coating (CF-MWCNT) and nitric acid treatment (CF-HNO₃) was compared. The performance of all these modified anodes was found to be better than bare electrode. The modified anodes were shown to significantly outperform the bare electrode anodes. CF-MWCNT and CF-HNO₃ modification increased the maximum power density by 1.60 and 2.88 times to 107 and 193 mw/m², respectively, compared to the bare electrode anode (67 mW/m²). Due to the effect of the modifications, biofilm formation became more denser and stable, the biodegradation rate of organic matter increased and more efficient electron transfer was achieved on the anode surface. These results present effective and simple methods to enhance power generation with carbon fiber electrodes and also suggest ideas that can further improve the performance of modified carbon fiber electrodes. The content of algal biomass obtained in the cathode chamber was analyzed and the highest biomass with 0.71 g/L was obtained in the cell with CF-HNO₃ anode. Carbohydrate, protein and lipid contents were found to be 55%, 15.4% and 24%, respectively. In conclusion, this study demonstrates that surface modifications of carbon fiber anodes are an effective method to enhance the power generation performance of microbial fuel cells and reveals that this approach offers a viable strategy to improve energy efficiency.