Recovery of Iron, Nickel, and Copper in Waste Water from Printed Circuit Board Manufacture by Electrodialysis Method

The electrodialysis method is used to recover iron, nickel and copper from waste water generated in the manufacture of printed circuit boards. The objects of study were ion-exchange membranes PC Acid 60 (PCCell GmbH) and CM (H) RALEX® (MEGA) and model solutions containing heavy metal ions (Fe3+, Ni2+, and Cu2+) and SO42– и NO3– anions. The time dependences of the retention coefficients of the Fe3+, Ni2+, and Cu2+ cations were constructed, the degree of treatment of the solutions to remove the SO42– и NO3– anions was determined, and the ion fluxes and ion transport numbers were calculated. On separating solutions containing one and all three salts of the target metals, the retention coefficients of Ni2+ and Cu2+ cations differ significantly, whereas those of Fe3+ cations, on the contrary, differ by no more than 2–3%. On separating a multicomponent three-salt solution, the retention coefficients of Ni2+ and Cu2+ cations are decreased in comparison with the corresponding values for single-salt solutions. For the purpose of exhaustive metal recovery, the electrodialysis separation of multicomponent solutions is the most efficient method, as applied to Fe3+ and Cu2+ cations.