Separation of zinc ions from synthetically prepared brackish water using electrodialysis: effect of operating parameters

Abstract

The removal of zinc(II) at low concentrations from an aqueous saline solution was investigated using a five-compartment electrodialysis cell. In this work, the effect of key operating parameters such as initial zinc ions concentration, solution pH, applied voltage, and feed flow rate on process efficiency was studied. The separation performance was evaluated in terms of mass transfer, energy consumption, and current efficiency. The results showed that increasing the initial concentration of Zn(II) and applied voltage improves the cell performance. However, separation performance decreases with an increase in the flow rate. It was also found that specific power consumptions (SPC) are strongly dependant on ionic strength as the increase of ionic strength leads to an increase of the solution conductivity. Zinc removal rate and SPC were virtually constant and increased sharply when pH values ranged in the alkaline region.

Keywords:

• Electrodialysis
• Zinc removal
• Salted water