含聚合物老化油磁性复合纳米破乳剂研制及破乳机理OA

Polymer-containing aged oil has the characteristics of high mechanical impurity content,severe emulsification,high viscosity,high interfacial film strength and good stability.The use of conventional demulsifiers presents many problems such as difficult screening,difficult penetration,high demulsification temperature and large demulsifier dosage.In this study,under normal temperature and pressure conditions,Fe2+as oxidized to Fe3O4 nanoparticles by the redox method and simultaneously in-situ deposited on the surface of reduced graphene oxide(rGO)to prepare a magnetic composite nanomaterial Fe3O4-rGO.The morphology,structure and chemical properties of Fe3O4-rGO were characterized by TEM,SEM,FTIR,XRD and XPS,respectively,confirming that Fe3O4-rGO is a two-dimensional flake nanomaterial with Fe3O4 loaded in the layered structure of rGO.At low temperatures,when the usage concentration is 0.04%,the demulsification rate of aged oil can reach over 90%within 2 hours,and the water phase is clear.As the temperature increases,the dehydration rate and dehydration efficiency of Fe3O4-rGO for aged oil significantly improve.At 80℃,the dehydration rate is as high as 98.0%.The effect of pH value on the demulsification efficiency of Fe3O4-rGO was also studied.It was found that Fe3O4-rGO shows high demulsification effect under acidic and neutral conditions(pH=2.2～6.8),while the demulsification effect is poor under alkaline conditions.This is mainly because when the pH value is below 6.8,the electrostatic attraction between Fe3O4-rGO and emulsion droplets is dominant,and Fe3O4-rGO can well combine with interfacial active substances,thereby destroying the interfacial film.As the pH value increases,the electrostatic repulsion between Fe3O4-rGO and emulsion droplets increases,making it difficult for Fe3O4-rGO to adsorb onto the interfacial film,thus leading to a decrease in demulsification effect.Finally,the recyclability of Fe3O4-rGO greatly reduces the cost of demulsifier usage and also reduces the pollution and impact of demulsifier on the water and oil phases.This study not only provides a high-performance and recyclable demulsifier for the separation of polymer-containing aged oil,but also offers a new idea for the preparation of novel magnetic composite nanomaterials.