Electrochemical Crystallization for Phosphate Recovery in the Form of Vivianite by a Two-Chamber Electrolysis Cell Using Sacrificial Iron Anodes

A sequencing batch two chamber electrolysis cell was set up to recover phosphate(P) from synthetic wastewater containing KH2PO4 with different gradients.In the cell, ferrous iron goes into the liquor from iron-anode to precipitate soluble P and form vivianite.The two-chamber electrolytic cell provides a suitable pH range for the formation of vivianite without adding acid and alkali, which saves costs and avoids waste of resources. After repeated experiments with different gradients, the minimum phosphorus(P) removal efficiency was stably achieved at 97.17 %. After long-term operation, the P removal effect was not affected despite the fouling of the proton exchange membrane(PEM). Further analysis by XRD, FITR and SEM illustrated that the P recovery precipitated was vivianite.