Performance of sulfite/Fe^IIIEDTA fuel cell: Power from waste in flue gas desulfurization process

In conventional flue gas desulfurization processes, a large amount of sulfite (SO₃²⁻) is produced as a byproduct through dissolution of SO_2(g). Meanwhile, sulfite has a strong oxidizing power in an alkaline condition (E⁰= −0.93 V vs SHE), so we designed a fuel cell utilizing sulfite as a fuel and examined its performance. In the fuel cell, sulfite is oxidized at the anode into non-hazardous and stable sulfate. Simultaneously, Fe^IIIEDTA (ferric ethylenediaminetetraacetic acid) is reduced at the cathode, since the reduced form, Fe^IIEDTA, can be an effective nitric oxide absorbent in a flue gas NO_x removal process. Cell performance was enhanced with pH of electrolyte and operating temperature adjustments. The highest power density was 7.51 mW cm⁻² in strong alkaline anolyte and acidic catholyte conditions at 80 °C. This study shows that the chemical energy in waste originating from air pollutants could be a good electricity source.