Comparative study of electrocoagulation and coagulation-flocculation effects on the destabilization of cutting oil emulsion
This work focuses on the breakdown of an Algerian cutting oil emulsion (Tasfalout 22/B) by batch electrocoagulation (EC) using iron electrodes. The efficiency of the process was estimated from turbidity measurements. An improved efficiency of destabilization was obtained by increasing the current density from 50 to 350 A•m‐2, over an electrolysis time of 15 min and using cutting oil concentrations of 1% (w/w), 2% (w/w) and 4% (w/w). Monitoring of the kinetics of the electrode dissolution over a period of 120 min showed that a similar process efficiency was obtained by decreasing the electrolysis time and by increasing the current density. A 99% removal of turbidity was obtained for an emulsion of 4% (w/w) with a current density of 150 A•m‐2 and an electrolysis time of 120 min. A comparison of the performances of electrocoagulation and of coagulation-flocculation with hydrated ferric chloride (FeCl3•6H2O) processes was carried out, with respect to the destabilization of cutting oil emulsion. This comparison highlighted the advantage of the coagulation-flocculation process for the of 1% (w/w) emulsion at different electrocoagulation current densities. However, for a current density of 150 A•m‐2, the removal efficiency of both processes was similar for the emulsion with higher cutting oil concentrations (2% (w/w) and 4% (w/w)). The pH of the emulsion obtained by the two processes following treatment varied. The medium remained alkaline during the electrocoagulation process and became acidic during the coagulation-flocculation process.