ÉLIMINATION DU CHROME HEXAVALENT D’UNE SOLUTION SYNTHETIQUE EN MODE DISCONTINUE AVEC ELECTRODES EN ACIER ORDINAIRE ET INOXYDABLE PAR COUPLAGE ÉLECTROCOAGULATION-ÉLECTROFLOTTATION

Abstract

The objective of our study is the application of an electrochemical process for the removal of Cr(VI) [toxicion] by electrochemical reduction of Cr(VI) to Cr(III) then its precipitation in the form of chromium hydroxide Cr(OH) 3.For the study of the efficiency of the process, tests were carried out with synthetic solutions by use of steel type anode and stainless steel typecathode. The results show that coupling electrocoagulation/electroflottation(EC/EF) is effective for the elimination of Cr(VI) with 99% for 50min of treatment. This performance is allotted to the combined effect ofFecoagulant produced at anode and hydrogen bubbles produced atcathode. Effects of the following operational parameters: initial pH, intensity of current, time, initial concentration of Cr(VI) and the nature and the concentration of support electrolyte were studied. A rate of elimination of 99, 8% of Cr(VI) was reached for 40 min, with density of current 66 A/m 2 , conductivity of 15mS/cm corresponding to 10 g/L of KCl.It was also observed that the consumption of energy decreases with the increase of conductivity, and reduction of the density of current. After the treatment,mud scraped underwent a characterization by diffractions of x-rays (RDX) in order to identify its composition