Composite of graphitic carbon nitride and TiO2 as photo-electro-catalyst in microbial fuel cell

The widespread application of surfactants and their subsequent discharge in the receiving water bodies is a very common issue in developing countries. In the present investigation, a composite of graphitic carbon nitride (GCN) and TiO2 was used as a photo-electro-catalyst in a microbial fuel cell (MFC)-based hybrid system for bio-electricity production and simultaneous pollutant removal (organic matter and sodium dodecyl sulphate, SDS). The GCN: TiO2 composite with a ratio of 70:30 (by wt. %) revealed a better electrochemical response; thus, it was used as a photo- electro- catalyst in MFC. Additionally, the photochemical characterization indicated a decrease in the band gap and charge recombination of GCN-TiO2 composite compared to standalone TiO2, which indicated a conducive effect of GCN addition. Further, on the actual use as a photoelectro-catalyst, the GCN-TiO2 catalysed MFC attained 58.2 +/- 9.6% and 86.5 +/- 7.1% of COD and SDS removal; while simultaneously harvesting a maximum power density of 1.07 W m(-3), which was higher than standalone TiO2- catalysed MFC. The follow-up treatment in the charcoal bio-filter and photo-cathodic chamber of the hybrid system further improved the overall COD and SDS removal efficiency to 92.1 +/- 2.7 and 95.6 +/- 1.5%, respectively. The electro-catalytic performance of the GCN-TiO2 can be attributed to the presence of nitrogen-active species in the composite. The results of this investigation demonstrated a potential MFC-based hybrid system for the simultaneous secondary and tertiary treatment of municipal wastewater. Consequently, the outcome of this investigation indicates an innovative research direction in the field of photoelectro-catalyst, which can fit into the role of a photo-catalyst as well as an electro-catalyst.

Automated summary

The widespread application and subsequent discharge of surfactants in developing countries is a common issue. In this study, a composite of graphitic carbon nitride (GCN) and TiO2 was used as a photo-electro-catalyst in a microbial fuel cell (MFC)-based hybrid system for bio-electricity production and simultaneous pollutant removal. The GCN-TiO2 composite showed better electrochemical response and achieved higher removal efficiency of COD and SDS compared to standalone TiO2. The results demonstrate the potential of this MFC-based hybrid system for municipal wastewater treatment and indicate an innovative research direction in the field of photoelectro-catalysts.