ELECTROCHEMICAL PHOSPHATE REMOVAL AND RECOVERY CELLS
Inventors: Kyoung-Shin Choi, Dohwan Nam, Ryan Belson
UW-Madison researchers have developed an electrochemical system that can not only selectively remove phosphate from a phosphate containing solution but also recover it as H3PO4 without needing additional acid or creating byproduct wastes. This system may offer a multitude of new opportunities to utilize phosphate wastes that are not currently recycled to create a sustainable phosphate cycle. The system is based on the discovery of an extraordinary ability of Bi to store and release phosphate through a reversible electrochemical solid-state conversion reaction between Bi and BiPO4. The phosphate removal/recovery system is composed of a phosphate-removal cell and a phosphate-recovery cell. In the phosphate-removal cell, a Bi electrode serves as the anode and is oxidized to BiPO4, storing phosphate. When the conversion of Bi to BiPO4 is completed, the resulting BiPO4 electrode will serve as the cathode in the phosphate recovery cell, where it is reduced back to Bi, releasing phosphate to the solution, and producing H3PO4.
- Performs well in high phosphate concentrations such as steel making
- Recovers high purity phosphoric acid or phosphate solutions (no need for additional acid)