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Lekhlif B.,Equipe de recherche Hydrogeologie | Oudrhiri L.,Equipe de recherche Hydrogeologie | Oudrhiri L.,Hassan II University | Oudrhiri L.,University of Québec | And 3 more authors.
Journal of Materials and Environmental Science | Year: 2014

The coagulation-flocculation is one of the techniques used for the treatment of industrial wastewaters. In this process, the principle of treatment consists on destabilizing negative colloidal particles, by addition of salts metal cations. The positive charge of cations compresses the electrical double layer which surrounds the colloidal particles characterized by a negative potential (ζ, Zeta Potential). The iron and aluminum salts are the most used. Electrocoagulation is derived from the conventional coagulation technique. The cations are generated in solution by electrolytic dissolution of the metal electrodes. The main advantages of this process, highlighted by several authors, are low dose of coagulant, reduction of salinity, enhanced reactivity of metal cations, oxidation of certain pollutants, compactness of installations, lower volume of sludge, and elimination of the small size colloidal particles. This paper reports a research work on wastewaters eletrocoagulation of an electroplating industry located in Casablanca (Morocco). The goal is to carry out some tests of depollution applying two voltages 6 and 12 V on aluminum electrodes and to evaluate its performance. Abatement rates determined for 6 V reached 57%, 63% and 42%, and 12 V for 77%, 88% and 66%, respectively for Chemical Oxygen Demand (COD), nickel and chromium. The elimination of these pollutants was done by adsorption on aluminum hydroxide or its polymers which were formed in the pH range of this study, but also by the precipitation of nickel (II) and chromium (III) which forms afterward the cathodic reduction of chromium (VI).

Lekhlif B.,Equipe de recherche Hydrogeologie | Eddaqaq F.,Equipe de recherche Hydrogeologie | Eddaqaq F.,Hassan II University | Dani A.,Hassan II University | And 5 more authors.
Physical and Chemical News | Year: 2013

The purpose of this study is to investigate the role of the clay associated with the effect of agitation on electrocoagulation of a synthetic water prepared in the laboratory with soil and water, simulating the groundwater. Electrocoagulation test is carried out in a batch reactor, with two aluminum electrodes, flat and parallel, powered by a voltage of 2.6 V. Ions released by electrolysis are agitated by a mechanical agitator blade (helical and flat). With the agitator of helical blades brewing between the clay material and floc of Al(OH)3 precipitating, was not held. This is due to the electroflotation of the clay by microbubbles released at the electrodes. The removal efficiency of turbidity is only 39%. The use of an agitator equipped with a flat blade made a net removal of turbidity, the yield reached 95.2%. This is related to the interactions between the clay and Al(OH)3 giving a complex species including metal bridge between the aluminum ions and the clay layer. The analysis by X-ray diffraction (XRD) of the solid material (raw clay and solid matter obtained after electrocoagulation) confirmed the results and highlighted the physicochemical reactions between the clay and Al (OH)3.

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