Synthesis and characterization of a novel reticulated multi-branched fluorinated polyether demulsifier for w/o emulsion demulsification

Preparation and demulsification performance of magnetic demulsifier Fe3N@F

Given the suboptimal emulsification performance and the potential for secondary pollution posed by existing demulsifiers, a facile and highly efficient fluorinated magnetic demulsifier (Fe3N@F) was synthesized via a one-step approach using fluorinated polyether and iron nitride as raw materials.The morphology and structure of the demulsifier were characterized using Fourier transform infrared spectroscopy (FTIR), scanning electron microscopy (SEM), thermogravimetric analysis (TGA), and X-ray photoelectron spectroscopy (XPS). The results confirm a successful fluoropolyether coating on the surface of iron nitride. The demulsifying and dehydrating properties were assessed through demulsifying and dehydrating experiments, and the influence of demulsifier addition and demulsifying temperature on the demulsification performance was investigated. Additionally, the demulsification mechanism was analyzed by the microscopic demulsification process. The results indicated that under the condition of the optimum demulsification temperature of 45 °C and the optimum demulsifier dosage of 150 mg L-1, the water removal (%) of the magnetic demulsifier containing fluorine (Fe3N@F) was the highest, and could reach 89.4%. Fe3N@F exhibited excellent magnetic response, the demulsifying rate could reach above 70% after recycling and reusing it 6 times. The application of iron nitride in demulsification presents a novel thought for the advancement of magnetic demulsifiers.

Investigation of Dioctyl Sodium Sulfosuccinate in Demulsifying Crude Oil-in-Water Emulsions

This research investigated the performance of dioctyl sodium sulfosuccinate (DSS), a double-chain anionic surfactant, in breaking crude oil-in-water emulsions. The response surface methodology was used to consider the effect of the DSS concentration, oil concentration, and shaking time on demulsification efficiency and obtain optimum demulsification conditions. Further single-factor experiments were conducted to investigate the effects of salinity, crude oil conditions (fresh and weathered), and gravity separation settling time. The results showed that DSS efficiently demulsified stable emulsions under different oil concentrations (500-3000 mg/L) within 15 min shaking time. Increasing DSS concentration to 900 mg/L (critical micelle concentration) increased the demulsification efficiency to 99%. DSS not only improved the demulsification efficiency but also did not impede the demulsifier interfacial adsorption at the oil-water interface due to the presence of the double-chain structure. The low molecular weight enables the homogeneous distribution of DSS molecules in the emulsion, leading to a high demulsification efficiency within 15 min. Analysis of variance results indicated the importance of considering the interaction of oil concentration and shaking time in demulsification. DSS could reduce the total extractable petroleum hydrocarbons in the separated water to <10 mg/L without gravity separation and could achieve promising demulsification performance at high salinity (36 g/L) and various concentrations of fresh and weathered oil. The demulsification mechanism was explained by analyzing the microscopic images and the transmittance of the emulsion. DSS could be an efficient double-chain anionic surfactant in demulsifying stable oil-in-water emulsions.