One-pot preparation of environmentally friendly, high demulsification rate and novel functional magnetic demulsifier: Used for oil and water separation in crude oil emulsion

In this paper, a novel functional magnetic nano-demulsifier with efficient oil–water separation and recyclability was prepared by one-pot method. Magnetic fluorinated polyether composite demulsifier (Fe3O4@C-F) was prepared by combining Fe3O4 as magnetic matrix with carbon nanospheres and grafting fluorinated polyether. The morphology and structure of the composites were analyzed by scanning electron microscopy (SEM), Fourier transform infrared spectroscopy (FTIR) and transmission electron microscopy (TEM). The results showed that carbon nanospheres and fluorinated polyether were successfully compounded on Fe3O4, and the crystallinity of the composites was improved. The demulsification experiment and recovery performance test were carried out with the self-made crude oil emulsion. The main factors affecting the demulsification performance of demulsifier and its demulsification mechanism were discussed. The results showed that the demulsification effect of Fe3O4@C-F was the best when the dosage was 600 ppm, 65 °C, 120 min and pH value was 6. The demulsification rate could reach 96.68%, and the oil–water interface was clear. Fe3O4@C-F had magnetic response, and could be recycled and reused 5 times from two-phase system under external magnetic field. The application of carbon materials in the field of oil–water separation has injected a new power source for the application of carbon nanomaterials in the field of demulsifiers.