Valorization of abandoned mine wastewater for the production of energy in a reverse electrodialysis cell

The study explores the technical feasibility of using abandoned mining site wastewater, specifically acid mine drainage (AMD), as an electrode solution in a reverse electrodialysis (RED) stack for energy production. Through experiments using a RED cell with varying electrode solutions, it was determined that the system achieved a maximum power density of 0.327 W m(-2) (cell pair) (5.01 W m(-2) (electrode)) when using simple mixtures of Cu2+ and Fe2+ ions, aligning with previous research on the Fe2+/Fe3+ redox pair. Synthetic solutions mimicking AMD composition also yielded promising results. When operating the system with real AMD effluent from an aban-doned mine, a slightly lower maximum power density of 0.137 W m(cell)(-2) pair was achieved, only 5.5 % lower than with synthetic AMD. An extended-duration test showed a minor increase in pH in the electrode solution, but importantly, no metal deposition occurred on the electrode surface, as the pH consistently remained below 3.5 throughout the test. These findings indicate the potential of AMD as a viable electrode solution, offering a promising avenue for further research in the development of more sustainable RED systems.