Energy Capture from Thermolytic Solutions in Microbial Reverse-Electrodialysis Cells

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Science  01 Mar 2012:
DOI: 10.1126/science.1219330


Reverse electrodialysis allows for capture of energy from salinity gradients between salt and fresh waters, but potential applications are currently limited to coastal areas and the need for a large number of membrane pairs. Using salt solutions that could be continuously regenerated using waste heat (≥40°C) and conventional technologies would allow much wider applications of salinity-gradient power production. We used reverse electrodialysis ion-exchange membrane stacks in microbial reverse-electrodialysis cells to efficiently capture salinity gradient energy from ammonium bicarbonate salt solutions. The maximum power density using acetate reached 5.6 W/m2-cathode surface area, which was five times that produced without the dialysis stack, and 3.0 ± 0.05 W/m2 with domestic wastewater. Maximum energy recovery with acetate reached 30 ± 0.5%.