Demulsification of crude oil emulsion using carbonized cotton/silica composites

Abstract

As a substitute for conventional oilfield chemicals, biomass-based composite materials have received extensive attention. In this study, degreasing cotton (DC) and tetraethyl orthosilicate (TEOS) were used as raw materials to synthesize carbonized cotton coated with SiO2 (CC@SiO2). CC@SiO2 was characterized by Fourier-transform infrared spectroscopy (FT-IR), X-ray spectroscopy (XRD), field-emission scanning electron microscopy (FE-SEM) and energy dispersive X-ray spectrometer (EDS). The effect of vital factors such as CC@SiO2 dosage, settling time and temperature on the demulsification performance was investigated. The optimal demulsification efficiency (DE) could reach 90.38% after demulsifying with 400 mg/L of CC@SiO2 at 65 ℃ for 120 min. The demulsification mechanism was studied by investigating the dynamic interfacial tension (IFT), interfacial activity and wettability. Additionally, the flocculation and aggregation of water droplets and separation of oil-water in emulsion were observed by the optical microscope. The current work indicates that CC@SiO2 is a simple, high-efficient demulsifier for the separation of the water-containing crude oil, which shows a good application prospect in oil industry.