Light intensity affects the performance of photo microbial fuel cells with Desmodesmus sp. A8 as cathodic microorganism

The performance of photo microbial fuel cells (photo-MFCs) with Desmodesmus sp. A8 as cathodic microorganism under different light intensities (0, 1500, 2000, 2500, 3000, 3500lx) was investigated. The results showed that illumination enhanced the output of the photo-MFC three-fold. When light intensity was increased from 0 to 1500lx, cathode resistance decreased from 3152.0 to 136.7Ω while anode resistance decreased from 13.9 to 11.3Ω. In addition, the cathode potential increased from −0.44 to −0.33V (vs. Ag/AgCl) and reached a plateau as the light intensity was increased from 1500lx to 3500lx. Accompanied with the potential change, dissolved oxygen (DO) within the cathode biofilm increased to 13.2mgL−1 under light intensity of 3500lx and dropped to 7.5mgL−1 at 1500lx. This work demonstrated that light intensity profoundly impacted the performance of photo-MFC with Desmodesmus sp. A8 through changing the DO.