Treatment of electroplating wastewater containing Cu2+, Zn2+ and Cr(VI) by electrocoagulation.
The performance of electrocoagulation, with aluminium sacrificial anode, in the treatment of metal ions (Cu2+, Zn2+ and Cr(VI)) containing wastewater, has been investigated. Several working parameters, such as pH, current density and metal ion concentrations were studied in an attempt to achieve a higher removal capacity. Results obtained with synthetic wastewater revealed that the most effective removal capacities of studied metals could be achieved when the pH was kept between 4 and 8. In addition, the increase of current density, in the range 0.8-4.8 A dm(-2), enhanced the treatment rate without affecting the charge loading, required to reduce metal ion concentrations under the admissible legal levels. The removal rates of copper and zinc were found to be five times quicker than chromium because of a difference in the removal mechanisms. The process was successfully applied to the treatment of an electroplating wastewater where an effective reduction of (Cu2+, Zn2+ and Cr(VI)) concentrations under legal limits was obtained, just after 20 min. The electrode and electricity consumptions were found to be 1 g l(-1) and 32 A h l(-1), respectively. The method was found to be highly efficient and relatively fast compared to conventional existing techniques.
Adhoum
Nafaâ
N
Centre Urbain Nord, Département de Chimie, Institut National des Sciences Appliquées et de Technologies, B.P. No. 676, 1080 Tunis Cedex, Tunisia. nafaa.adhoum@insat.run.tn
Monser
Lotfi
L
Bellakhal
Nizar
N
Belgaied
Jamel-Eddine
JE
D002857:Chromium / Q000302:isolation & purification*; D003300:Copper / Q000302:isolation & purification*; D004564:Electrocoagulation / Q000379:methods*; D004595:Electroplating; D006863:Hydrogen-Ion Concentration; D007220:Industrial Waste / Q000517:prevention & control*; D009994:Osmolar Concentration; D014877:Water Pollution, Chemical / Q000517:prevention & control*; D015032:Zinc / Q000302:isolation & purification*
D007220:Industrial Waste; D002857:Chromium; C074702:chromium hexavalent ion; D003300:Copper; D015032:Zinc