Recovery of nickel and water from wastewater with electrochemical combination process

Abstract

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, ⩾500mg/L) and low concentration wastewater (LCW, <500mg/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 1mg/L) by the combination process, with the energy consumption of EL≈25.7kWh/kg, ED≈0.5kWh/m3 and EDI≈0.2kWh/m3.