Performance of sulfite/FeIIIEDTA fuel cell: Power from waste in flue gas desulfurization process

Abstract

In conventional flue gas desulfurization processes, a large amount of sulfite (SO32−) is produced as a byproduct through dissolution of SO2(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, FeIIIEDTA (ferric ethylenediaminetetraacetic acid) is reduced at the cathode, since the reduced form, FeIIEDTA, can be an effective nitric oxide absorbent in a flue gas NOx 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.