Simultaneous Removal of Greases and Hexavalent Chromium from Electroplating and Chromate Conversion Coating Waste Solution by Electrocoagulation
2018
El-Ashtoukhy, E.-S. Z. | Abdel-Aziz, M. H. | Sedahmed, G. H.
Simultaneous removal of oil droplets and hexavalent chromium from synthetic wastewater of chromium plating and chromate conversion coating plants by electrocoagulation in a new cell design was studied under different conditions of pH, initial Cr⁶⁺ concentration, NaCl concentration, and current density. Under optimum conditions, more than 90% of oil content and Cr⁶⁺ were removed. Percent removal was found to increase with decreasing Cr⁶⁺; high Cr⁶⁺ concentrations tend to passivate the aluminum anode and decrease the percent removal of Cr⁶⁺ and oil. The effect of NaCl concentration shows a maximum percent removal at 1.5%. The pH range 4–5 was found to give the highest percent removal. Increase of current density was found to improve the percent removal of Cr⁶⁺ and oil droplets. The favorable effect the combined oil and Cr⁶⁺ removal on the capital and operating costs of wastewater remediation was pointed out. Potential merits of the present cell design compared to the traditional parallel plate cell were highlighted.
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