Cutting oil emulsion treatment by electrocoagulation using aluminum and iron electrodes

Abstract

In the present work, electrocoagulation process was tested in a monopolar batch reactor 0,6L using Aluminum (Al) and Iron (Fe) electrodes for the treatment of cutting oil emulsion used in the manufacture of mechanical parts of the tractor construction factory of ETRAG (Entreprise-TRactors-AGriculture), Constantine, Algeria. Different operational conditions such as initial pH, current density, spacing between electrodes and electrolysis time were examined. The optimal current density, initial pH, electrodes spacing and electrolysis time were found using a Response Surface methodology (RSM) to be 173A/m2, 6.8, 1.7 Cm, 42 min, respectively for Aluminum electrodes and 287 A/m2, 2 Cm, 44 min for iron electrodes. Under these optimal conditions, turbidity and COD reductions were respectively: (Al: 99.96%, Fe: 99.63%) and (Al: 98.08%, Fe: 96.70%). The individual and interactions effects of the independent variables on the responses were studied using a plot of three dimensional response surfaces. It was found that the most determining factors in the removal of cutting oil by EC, using aluminum and iron electrodes are the electrolysis time, current density. Moreover, Al electrodes were found to be more efficient than Fe ones in terms of COD and Turbidity reductions. It should be mentioned, according to the obtained results, that the removal levels of turbidity and COD are not sufficient to meet discharge standards; therefore, EC would be perfect as a primary treatment which can be followed by another treatment such as biological one for instance.