MICROBIAL FUEL CELL FOR Cr(VI) REDUCTION AND SIMULTANEOUS BIO-ELECTRICITY PRODUCTION USING AN ABIOTIC CATHODE

This study's aim is to evaluate the removal efficiency of Cr(VI) and electricity generation using a dual chamber microbial fuel cell (MFC). Synthetic wastewater was utilized as a medium for the batch mode experiments. Particularly, this research examined the effect of the initial pH of the catholyte, in the range of 2 - 4, the continuous catholyte pH adjustment at pH 2 during cycle operation, as well as the effect of catholyte conductivity on the MFC performance. The best electrochemical performance (P-max of 58 mW m(-2)) was achieved at pH 2 with a Cr(VI) removal efficiency of 83.5%. However, the maximum power density drastically decreased (P-max 5.2 mW m(-2)) at pH 3 and no power production and Cr(VI) removal were observed at pH 4. Moreover, adjusting at 2 during cycle operation, did not enhance the performance of the cell, achieving a Cr(VI) removal efficiency of 52.5%. This was attributed to the back migration of protons to the anolyte, resulting from the pH adjustment. Furthermore, when KCl supporting electrolyte was not added in the catholyte, at pH 2, the conductivity decreased by 54.7%, which lead to a decrease of the Cr(VI) removal efficiency and the MFC electrochemical performance (P-max=8.2 mW m(-2)).