Demulsification and Purification of Petroleum Oily Wastewater Using Electrochemical Techniques
Abstract
This research deals with the treatment of oily wastewater effluents of petroleum refineries using hybrid electrocoagulation/electroflotation (EC/EF) techniques. A dynamic flow system was constructedusingan improved design of a compact electrochemical reactor containing two parallel vertical sheetsas electrodes.A galvanostatic transient techniquefor two types of electrodes, Al-Al and Al-C felt were used to achieve the hybrid (EC/EF) treatment in one reactor. Emulsified synthetic wastewater was prepared by mixing crude oil with deionized waterand sodium dodecyl was added as an emulsion stabilizing agent. Electrocoagulation produces Al3+ ions by corroding sacrificial anodes, releasing active coagulant precursors into the solution. Furthermore, the release of finely dispersed H2 gas bubbles at the cathode causes flog to lift to the upper surface of the solution.All experiments were carried out in continuous operation for two hours with a variety of operating conditions, including initial O/W concentration, current density, volumetric flowrate, and cathode type.Results revealed that for an initial O/W emulsion of 300 ppm and 30 mA/cm2 current density with different solution flowrate of2,4 and 6 L/hr the COD removal efficiency was 90,40 and 80% for Al-Al electrodes and 83,79 and78% for Al-C felt, respectively. The specific electrical energy consumption (SEEC) and the instantaneous current efficiency (ICE) for the demulsification experiments were also studied.
