Enhancing the efficiency of novel PCNF demulsifier for oil-contaminated wastewater treatment through numerical simulation optimization of demulsification mechanism

Abstract

This study used COMSOL simulation software to simulate the aggregation behavior of oil droplets under the action of a direct current electric field. Moreover, in-depth research was conducted on the aggregation process of oil droplets and the dynamic changes of the water oil micro interface. Research has found that the interfacial tension between water and oil is an important factor affecting the deformation of oil droplets. In this work, a new type of magnetic demulsifier (PCNF) was prepared using nano-Fe₃O₄ as the condensed core, sodium carboxymethyl cellulose (CMC-Na) as the binder, and polyferric sulfate (PFS), and this demulsifier was coupled with an electroflocculation process. The results indicate that the addition of PCNF can effectively reduce the interfacial tension between water and oil, promoting the demulsification process. Compared with traditional flocculants, the combination of electrochemical action and the optimal 2 g/L PCNF dosage provides higher purification efficiency. By introducing calcium chloride, the dosage of PCNF can be reduced. When the dosage is adjusted to 1.5 g PCNF + 0.5 g calcium chloride, the electrolysis time can be shortened from 180 min to 90 min. Under these treatment conditions, the COD in the emulsified oil wastewater is reduced to 46 mg/L and the oil content is reduced to 5.08 mg/L. Economic calculations show that compared to using PCNF alone, this reduction method can reduce operating costs by 39.83 %. This strategy achieves efficient demulsification and oil removal, lowers economic costs, and provides a solid foundation for guiding the development of practical technology.