Cadmium Removal from Phosphoric Acid by a Process Combining Ion Exchange on Resin and Electrodialysis

The cadmium removal from phosphoric acid using a hybrid process combining ion exchange resin and electrodialysis called electropermutation was investigated. Continuous electropermutation has been shown to be more effective than conventional electrodialysis with a cadmium removal rate of 70.70% versus 13.70%. The study of the influence of some operating parameters on continuous electropermutation has revealed that the cadmium removal efficiency increases with the applied current density, and the flow rate of the feed solution. However, the efficiency decreases as the phosphoric acid and cadmium concentration increases. The cation exchange resin and the electroregeneration electrolyte nature also have an effect on the continuous electropermutation efficiency. The Duolite C20 resin and the HNO3 electroregeneration electrolyte were found to be more effective in removing cadmium from phosphoric acid by continuous electropermutation.