Continuous electrodeionization for removal and recovery of Cr(VI) from wastewater

Continuous electrodeionization (CEDI) was investigated for removal and recovery of Cr(VI) from synthetic wastewater. Different anion exchange resins, including the gel strong-base resin, gel weak-base resin, macro-porous strong-base resin, and macro-porous weak-base resin, were examined. The gel strong-base resin was found to be the best one for use in CEDI. It was shown that CEDI could remove and recover Cr(VI) effectively from wastewater. After treatment, Cr(VI) concentration was reduced from initial 40–100 mg/L to 0.09–0.49 mg/L, and a pure chromic acid solution containing Cr(VI) as high as 6300 mg/L Cr(VI) was obtained. The current efficiency and energy consumption was 16.1–18.8%, and 4.1–7.3 kWh/mol Cr(VI), respectively.