Aqueous Phosphate Removal and Electricity Production Using an Iron–Air Fuel Cell

Abstract

Phosphorus (P) surplus is a key factor in water eutrophication, and aqueous phosphate removal is a concern. In this study, ferrous ions (Fe2+) were generated in situ by iron–air fuel cells and were used in the removal of P from synthetic P-containing wastewater. The P removal results indicated that different initial concentrations of P were more effectively removed by an in situ Fe2+ generation than by the addition of FeSO4. The main P removal products of FeSO4 were Fe hydroxides, whereas the main products with the iron fuel cell were vivianite and Fe hydroxides. These results suggested that Fe2+ formed in situ had a more conducive and stronger affinity to bond phosphate than FeSO4. The maximum power density reached 1,875 mW/m2 after 24 h of operation. The results indicate that the iron–air fuel cell can be used for P removal/recovery coupled with potential electricity generation.