Electrochemical Removal of Chromium from Wastewater

摘要

We carried out a study to determine the feasibility of electrochemically removingchromium from plating wastewater. Hexavalent chromium is a carcinogen and its discharge is required to be near 1 ppm. In our work we determined the effects of key variables including temperature, electrolyte flow rate, pH, and electrode composition. At the low chromium concentrations found in plating wastewater, we determined that the rate of chromium ion removal was mass transfer limited. Of the four electrode types tested, only gold gave significantly enhanced performance; however, graphite would probably be the most cost-effective for large-scale application. Chromium reduction rate was significantly increased at reduced pH. Because chromium ion solubility increases at lower pH, the higher removal rate would need to to be balanced against higher chromium redissolution rate in a practical system. A preliminary analysis based on our laboratory data indicates that a practical system based on electrochemical technology is feasible. WASTEWATER TREATMENT, CHROMIUM, ELECTROCHEMICAL PROCESS.