Separation of cottonseed oil from oil–water emulsions using electrocoagulation technique

The removal of cottonseed oil from oil–water emulsion by means of electrocoagulation was investigated in a cylindrical batch reactor. The effects of operating parameters such as, current density, initial oil concentration, pH and NaCl dosage on the oil removal efficiency have been studied. Current density (c.d.) ranged from 0.0009 to 0.02 A/cm2, the initial oil concentrations investigated were 200, 300 and 400 ppm, pH values used were 3, 5, 7, 9 and 11. Emulsion conductivity was changed using different concentrations of NaCl (1.5% and 3.5% and 85 ppm) as an electrolyte, to show its effect on the oil removal. The electrodes were made of steel in the form of horizontal intermeshing vanes, which is considered as a new geometry design. Also, power consumption (KW h/kg oil removed) was calculated to evaluate the economic aspects and their relation with the removal efficiency, in order to figure out the optimum parameters to work with. The oil removal efficiency showed its best values at high current density values, high initial oil concentration with an emulsion of pH around 7. Electrolyte concentration had insignificant effect on the oil removal, but increasing its concentration lowered the power consumption.