Recovery of nickel and water from wastewater with electrochemical combination process

Owing to its precious value and high toxicity, nickel recovery from wastewater is a worthwhile work. However, the concentration of Ni2+ varies from tens to thousands of mg/L due to different wastewater sources, no process can simultaneously meet the requirements of metal recovery and water reuse, both for high concentration wastewater (HCW, ⩾500 mg/L) and low concentration wastewater (LCW, <500 mg/L). In this paper, the feasibility of nickel recovery and water reuse was investigated using electrochemical combination processes: electrolysis (EL), electrodialysis (ED), and electrodeionization (EDI). First, nickel containing wastewater were separately treated by EL, ED and EDI, effects of there operating parameters, voltage, initial Ni2+ concentration, pH and water flux on the nickel recovery and water quality were investigated and optimized. Then, an EL-ED-EDI combination process was developed for nickel containing wastewater treatment. The results showed that almost 99.8% of nickel could be recovered with the purity of 93.9% and almost 100% of water could be reused (Ni2+ concentration was less 1 mg/L) by the combination process, with the energy consumption of EL ≈ 25.7 kW h/kg, ED ≈ 0.5 kW h/m3 and EDI ≈ 0.2 kW h/m3.