Removal and recovery of Ni2 + from electroplating rinse water using electrodeionization reversal

• EDIR has been proposed for removal and recovery of Ni2 + from dilute solution.
• The duration of polarity reversal should not be greater than 4 h.
• Stepwise stream switching mode was employed to reduce Ni2 + loss.
• Ni2 + removal efficiency was 97% and the concentrating factor was 79.2.

The removal and recovery of Ni2 + from simulated electroplating rinse water by electrodeionization reversal (EDIR), i.e., electrodeionization using periodic changes in polarity, was studied. Based on the EDIR characteristic curves, the appropriate applied stack voltage was determined to be 30 V. The influence of the polarity reversal period on EDIR performance was examined. In addition, a stepwise stream switching mode was proposed to reduce Ni2 + loss. The experimental results showed that the duration of polarity reversal should not be greater than 4 h to prevent the formation of metal hydroxide precipitates. Additionally, the EDIR process with a polarity reversal period of 4 h and stepwise stream switching mode exhibited good separation performance, removing 97.0% of Ni2 + from the feed solution and simultaneously recovering these ions into a concentrate stream with a high concentration of 3961 mg·L− 1. The current efficiency was 32.6%, and the corresponding energy consumption to treat 1 m3 of water was 1.02 KW·h. Thus, EDIR has considerable potential for the recovery and reuse of heavy metal ions from electroplating rinse water.