Environmentally friendly and cost-efficient recyclable demulsifiers are critical for dewatering of water-in-oil (W/O) emulsions. Here, a novel facile synthesis of magnetic-recyclable demulsifiers is reported. Three kinds of commercial polyether demulsifiers (AE1910, SP169, and AR321) are used and anchored onto Fe₃O₄ nanoparticle surfaces using mussel-inspired polydopamine as an adhesive. Infrared spectra, transmission electron microscopy imaging, dynamic light scattering, thermogravimetric analysis, and X-ray diffraction are employed. The results confirm successful polydopamine coating on nanoparticle surfaces (Fe₃O₄@PDA) and follow the binding of polyether demulsifiers (Fe₃O₄@PDA@AE1910). A water contact angle of 91.3° measured on Fe₃O₄@PDA@AE1910 indicates particle amphiphilicity for promising interfacial activity. A low interfacial tension (∼1.0 mN⋅ m⁻¹) and a rapid adsorptive behavior are observed for the oil-water interface with the presence of Fe₃O₄@PDA@AE1910. The three kinds of nanoparticles report high demulsification efficiency of 98.00 %, 91.63 %, and 94.33 % for crude oil emulsions. They also record 98.25 %, 90.27 %, and 98.66 % for water/n-decane emulsions for Fe₃O₄@PDA@AE1910, Fe₃O₄@PDA@SP169, and Fe₃O₄@PDA@AR321, respectively. These nanoparticles can be magnetically recovered and reused. As high as 77.81 % remaining demulsification efficiency is reached after eight cycles of treating water/n-decane emulsion and three cycles of treating crude oil emulsions by using Fe₃O₄@PDA@AE1910. The findings indicate a promising application of polydopamine-coated Fe₃O₄ nanoparticle to prepare various magnetic recyclable nanoparticle demulsifiers in dewatering of W/O emulsions. Compared with previous reports, the synthetic process is simple, and the synthetic condition is temperate and environmentally friendly, which may advance the application of recyclable nano-demulsifiers in the oil field.

环保且具有成本效益的可循环使用的破乳剂对于油包水（W / O）乳液的脱水至关重要。在此，报道了一种新型的磁性可再循环破乳剂的简便合成方法。使用了三种市售的聚醚破乳剂（AE1910，SP169和AR321），并使用贻贝启发式聚多巴胺作为粘合剂将其锚定在Fe ₃ O ₄纳米颗粒表面上。使用红外光谱，透射电子显微镜成像，动态光散射，热重分析和X射线衍射。结果证实了聚多巴胺在纳米颗粒表面（Fe ₃ O ₄ @PDA）上的成功涂层并遵循了聚醚破乳剂（Fe ₃ O ₄）的结合@ PDA @ AE1910）。在Fe ₃ O ₄ @ PDA @ AE1910上测得的91.3°的水接触角表明该颗粒具有两亲性，具有良好的界面活性。在Fe ₃ O ₄ @ PDA @ AE1910的存在下，油水界面观察到低的界面张力（〜1.0 mN·m ^-1）和快速的吸附行为。三种纳米颗粒对原油乳液的破乳效率很高，分别为98.00％，91.63％和94.33％。他们还记录了水/正癸烷乳液的Fe ₃ O ₄ @ PDA @ AE1910，Fe ₃ O ₄ @ PDA @ SP169和Fe ₃ O _4的98.25％，90.27％和98.66％。@ PDA @ AR321。这些纳米颗粒可以被磁性回收和再利用。通过使用Fe ₃ O ₄ @ PDA @ AE1910处理水/正癸烷乳液的八个循环和处理原油乳液的三个循环后，达到高达77.81％的剩余破乳效率。这些发现表明，聚多巴胺涂覆的Fe ₃ O ₄纳米颗粒在制备W / O乳液脱水中制备各种磁性可循环使用的纳米颗粒破乳剂方面具有广阔的应用前景。与以前的报道相比，合成工艺简单，合成条件温和，环保，可以促进可回收纳米破乳剂在油田的应用。