Technical Note

Electroplating wastewater treatment through chemical precipitation and electrodialysis

C. Peng^1,2, S. Song^1,*, S. Lu², A. López-Valdivieso<sup>1

1</sup>Instituto de Metalurgia, Universidad Autónoma de San Luis Potosí, Av. Sierra Leona 550,
San Luis Potosí, C. P. 78210, México;
²Department of Environmental Engineering, University of Science and Technology Beijing,
Beijing, 100083, P. R. China



Received 22 November 2002; accepted 20 July 2004



ABSTRACT

In the present work, treatment of an electroplating wastewater in a high chromium concentration has been studied through chemical precipitation (CP) and electrodialysis (ED). It has been found that chemical precipitation or electrodialysis alone could not produce a qualified water to be recycled to electroplating lines as rinsing water. Accordingly, a novel process, combined chemical precipitation and electrodialysis (CP-ED), has been tested on the wastewater. The experimental results have shown that the CP-ED process greatly eliminated chromium from the wastewater, about 95% Cr (VI) removal, leaving the cleaned water assaying 0.18mg/l Cr(VI). Also, the CP-ED process effectively removed other ions such as Na+ and Cl that were involved into the wastewater because of adding precipitants in the CP step. Compared with CP treatment, CP-ED process allowed a large saving at reagent cost and operation cost, and less environmental concerns.



Keywords: Electroplating wastewater, Chemical precipitation, Electrodialysis



* Corresponding author
   E-mail : shaoxian@uaslp.mx