Electrochemical Bi/BiPO4 Cells for a Sustainable Phosphate Cycle

Phosphorus is one of the main components of fertilizer and is also essential for various industrial manufacturing processes. While a continued increase in human population will require more fertilizer production, global phosphate rock reserves are limited. Furthermore, the collection of phosphate rock, its conversion to phosphoric acid, and disposal of phosphate create various environmental concerns. Here, we demonstrate intriguing electrochemical properties of Bi/BiPO4 electrodes which are used to construct phosphate removal and recovery cells. The Bi/BiPO4 cells selectively remove phosphate from a solution via a phosphate-specific electrode reaction and directly recover it as phosphoric acid without needing additional acid or generating any byproduct wastes. This discovery offers an unprecedented opportunity to produce phosphoric acid using phosphate wastes, which can lead to a sustainable phosphate cycle.