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[Display omitted] • RHC-0.5 was prepared via a simple one-step hydrothermal route. • RHC-0.5 has high demulsification efficiency in water-in-crude oil. • The demulsification efficiency of RHC-0.5 is similar to commonly commercial demulsifiers. • RHC-0.5 is low-cost and environmentally-friendly and easily prepared. Demulsification of crude oil emulsions still face many difficulties in the petroleum industry. Therefore, it is very important to develop innovative materials to achieve the effective separation of oil–water emulsions. In this work, an environmentally friendly RHC-0.5 demulsifier was prepared via a simple one-step hydrothermal route using rice husk (RH) as raw materials. It was characterized by Fourier transform infrared spectroscopy, X-ray photoelectron spectroscopy, field-emission scanning electron microscopy, energy dispersive X-ray spectrometer and thermogravimetric analysis. The possible breaking mechanism was analyzed by particle size analysis, Zeta potential, interfacial activity, interfacial tension, self-assemble of interfacial film and microscopic analysis. The influence of some important factors such as dosage, temperature, standing time and salinity on the demulsifying efficiency (DP) was explored through bottle tests. The optimal DP of 95.01 % could be obtain with 300 mg/L of RHC-0.5 at 70 °C for 10 min. Meanwhile, RHC-0.5 had a good salt tolerance even at the salinity of 40000 mg /L. In addition, its DP was compared with that of commercial demulsifiers such as SP169, CH-66 and AR-32. This work not only can promote the efficient utilization of biological waste (RH), but also provides an insight into the exploration of new demulsifying materials with excellent performance. [ABSTRACT FROM AUTHOR]

Removing emulsified water from a water-in-crude oil (W/O) emulsion is critically required prior to downstream processing in the petroleum industry. In this work, environmentally friendly and amphipathic rice husk carbon (RHC) demulsifier was prepared by a simple carbonization process in a muffle furnace using rice husks as starting materials. RHC was characterized by field-emission scanning electron microscope, energy dispersive spectrometer, Fourier transform infrared spectrometer, ultraviolet–visible spectrometer, powder X-ray diffraction, zeta potential and synchronal thermal analyzer. The factors such as dosage, temperature, settling time, pH value and salinity were systematically investigated. The results indicated that the dehydration efficiency (DE) reached as high as 96.99% with 600 mg/L of RHC for 80 min at 70 °C. RHC exhibited an optimal DE under neutral condition, but it was also effective under acidic and alkaline conditions. Also, it had an excellent salt tolerance. The possible demulsification mechanism was explored by interfacial properties, different treatment methods for RHC and microexamination. The demulsification of RHC is attributed to its high interfacial activity, oxygen-containing groups and content of silica. It indicates that RHC is an effective demulsifier for the treatment of the W/O emulsion. [Display omitted] • Rice husk carbon (RHC) was obtained using biomass as raw material. • No chemical was used in the simple preparation process. • The demulsification efficiency of W/O emulsion by RHC could reach 96.99%. • RHC had a wide pH range and good salt tolerance. [ABSTRACT FROM AUTHOR]

In order to reduce the cost of demulsifiers and improve the demulsification performance of carbon material demulsifier, the nano-SiO 2 was grafted onto the surface of oxidized carbon black (Ox-CB) by sol-gel method in current study. The novel composite demulsifier was analyzed by fourier transform infrared spectroscopy (FT-IR), field-emission scanning electron microscope (FE-SEM), energy dispersive X-ray (EDX) and X-ray diffraction spectra (XRD) which confirmed the partial grafting of SiO 2 on the oxidized carbon black (Ox-CB).The influences of temperature, settling time, and concentration of the composite demulsifier on the efficiency for breaking up water-in-oil emulsions were investigated in detail by bottle test. It was found that the best operating conditions to remove more than 90% of the water from the original emulsion were a temperature of 75 ℃ and a demulsifier concentration of 500 mg/L. The wettability, oil-water interfacial tensions (IFT) and interfacial activity of the demulsifier were further measured to explore the demulsification mechanism. Possible demulsification mechanism showed that the composite demulsifier could lead to the breakup of water-in-oil emulsions by bridging, flocculation and coalescence. The high interfacial activity is the main factor affecting the demulsification. [ABSTRACT FROM AUTHOR]

• The synthesis step of the demulsifier is extremely simple. • The demulsifier has a good performance and application potential. • This work provides a new idea for explanation of demulsification mechanism. • The demulsifier can greatly shorten time and reduce temperature of demulsification. A three-branch structure demulsifier (GTE-DDA) for the treatment of water-in-crude oil (W/O) emulsions was synthesized by a one-step method using glycerol triglycidyl ether (GTE) as core and dodecyl amine (DDA) as branched chain. It was characterized by Fourier-transform infrared spectroscopy (FT-IR), nuclear magnetic resonance hydrogen spectra (1H NMR) and thermogravimetric analysis (TGA). Some key parameters such as the concentration of GTE-DDA, settling time, operated temperature and salinity on demulsification efficiency (DE) were systematically explored. The DE reached 87.55% after treating with 400 mg/L of GTE-DDA at 50 °C for 30 min. The demulsifying temperature was significantly lower than those reported in literatures (60-80℃). Especially, a rise in temperature could further improved the DE. In addition, GTE-DDA had an excellent salt tolerance. The possible mechanism was investigated by the interfacial tension (IFT), three-phase contact angle (CA) and microscopic observation. The comparison with commercial demulsifiers showed that GTE-DDA had a great potential for the treatment of crude oil emulsions. [ABSTRACT FROM AUTHOR]

Water-in-oil emulsions are frequently encountered in petroleum extraction. In this paper, CRB-SiO 2 , a cost-efficient and environmentally friendly demulsifier, was synthesized by a two-step method. The chemical structure and surface morphology were analyzed by flourier transform infrared spectroscopy (FT-IR) and scanning electron microscopy (SEM), respectively. The effect of salinity, concentration, temperature and pH value on the demulsification efficiency (DE) was investigated in detail. The DE reached 93.98% with 600 mg/L of CRB-SiO 2 at 70 °C. Also, it had an excellent tolerance of salt, acid and alkali. Moreover, the demulsification mechanism was also studied through three-phase contact angle, interfacial tension and self-assembly of interfacial membrane. CRB-SiO 2 has an amphiphilic structure and lower interfacial tension (IFT) around 37.75 mN/m. Accordingly, it can be easily adsorbed at the water-oil interface, destroying the interface membrane and initiating the separation of oil and water. In summary, CRB-SiO 2 has a potential application in petrochemical industry. [Display omitted] • CRB-SiO 2 was prepared by a two-step method. • CRB-SiO 2 has high demulsification efficiency in water-in-crude oil emulsion. • CRB-SiO 2 is environmentally friendly and highly economical because it uses waste rice bran as raw material. • CRB-SiO 2 has an excellent tolerance of salt, acid and alkali. • The demulsification mechanism has been deeply studied from many aspects. [ABSTRACT FROM AUTHOR]