Effectiveness of biophotovoltaics system modified with fuller-clay composite separators for chromium removal

The performance of biophotovoltaics (BPVs) having clay separators modified with 10, 15, and 20% of Fuller's earth-material (FEM) to improve the cation exchange capacity was assessed on the basis of wastewater treatment and electrochemical analyses. Among the three variants of clay separators other than the commercial proton exchange membrane (PEM), clay separator modified with 15% of FEM resulted in peak power density (7.87 W/ m3) with high organic matter removal (82 +/- 3.78%) and Cr (VI) reduction (94 +/- 0.85%). FEM provides cationic sites enhancing the proton transfer rate as confirmed from the electrochemical analysis. Membrane characterization also showed high proton transfer coefficient with low membrane resistance in FEM-15%. This first ever study on the utilization of the low-cost 15% FEM clay separator BPV achieved high power outputs and proved its suitability for field-scale applications due to its long-term stability, and thus can be an alternate to the costly polymeric membrane.

Automated summary

This study evaluated the performance of biophotovoltaics (BPVs) with clay separators modified with different proportions of Fuller's earth-material (FEM) for improved cation exchange capacity. The clay separator modified with 15% FEM exhibited the highest peak power density, as well as high rates of organic matter removal and Cr(VI) reduction. Electrochemical analyses confirmed that FEM provides cationic sites that enhance proton transfer rate. Additionally, membrane characterization showed high proton transfer coefficient and low membrane resistance in the FEM-15% separator. This low-cost separator demonstrated high power outputs and long-term stability, making it a viable alternative to expensive polymeric membranes for field-scale applications.