An evaluation of continuous electrode ionization as an in-line process for plating rinsewater recovery

The objective of this project was to investigate the ability of continuous electrodeionization (CEDI) to be used in a copper electroplating line to recover copper sulfate and purified water from rinsewaters for reuse within the same process. Typically, these acidic rinsewaters contain approximately 10 to 50 mg/L of copperas copper sulfate. This range of copper is much higher than any used in previous applications of CEDI technology. Three bench-scale configurations of CEDI modules were evaluated under varying flow and voltage conditions to test the performance of the process in treating the rinsewater. The influence of different ion exchange packings on CEDI performance was examined to determine which module design worked best for this separation process. The bench-scale test results suggest that CEDI is a potentially viable technology for copper sulfate recover, from waste rinsewaters generated by a copper electroplating line. A single stage CEDI process was able to produce a pure waterproduct containing non-detectable concentrations of copper; and an acidic copper sulfate concentrate with a copper concentration as high as 4,000 mg/L.