Energy and copper recovery from acid mine drainage by microbial fuel cells. Effect of the hydrochar doping on carbon felt anodes

This work investigates the performance of a Microbial Fuel Cell (MFC) for Acid Mine Drainage (AMD) treatment using bare and hydrochar-doped carbon felt (CF) anodes. Hydrochar was synthesized through hydrothermal carbonization of Spergularia rubra, followed by activation at 500 degrees C, resulting in improved O/C and H/C ratios of 0.26 and 0.78, respectively. The study reveals that doping CF anodes with non-activated and activated hydrochar significantly enhances copper recovery and electricity generation. The highest copper recovery rate of 16.0 mg/L h- 1 was achieved with activated hydrochar-doped CF (CFaH) anodes, followed by 10.6 mg/L h- 1 with nonactivated hydrochar-doped CF (CFnaH) anodes, and 7.1 mg/L h- 1 with bare CF anodes. Hydrochar doping also improved the maximum current density to 0.21 mA cm- 2 compared to 0.16 mA cm- 2 with bare CF anodes. These results demonstrate the potential of hydrochar-doped CF anodes for efficient metal and energy recovery from AMD, offering a sustainable and energy-efficient alternative to conventional methods.