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A highly branched PNDC demulsifier with 2,6‐naphthalenedicarboxylate as centronucleus was prepared by an efficient "one‐pot" strategy. The product was characterized by FT‐IR, 1H‐NMR, and TGA. The bottle test was performed to explore the effect of temperature, settling time, pH value, and concentration on the demulsification efficiency (DE). The DE reached an optimal value of 94.63% when the concentration of PNDC, settling time and operated temperature were 100 mg/L, 60 min and 70°C, respectively. Also, the DE could reach 91.58% when the concentration was only 20 mg/L at the same conditions. It showed that PNDC had an excellent performance in W/O emulsions with an extremely low concentration. Especially, PNDC could be used over a wide pH range (4–12) and high salinities, indicating that it had a good salt, acid and alkaline tolerance. In addition, the interfacial tension (IFT), surface tension (SFT), elastic modulus and micrograph analysis were carried out to investigate the possible mechanism. This work provides a highly branched demulsifier with high DE for the demulsification of stable W/O emulsions. [ABSTRACT FROM AUTHOR]

A large number of stable oil-in-water (O/W) emulsions are generated by the petroleum industry each year, resulting in a series of operational and environmental challenges. In this study, a RH-NH2 demulsifier was prepared for the separation of O/W emulsions by grafting ethylenediamine onto natural rice husk. RH-NH2 was characterized using Fourier transform infrared spectroscopy (FT-IR) and scanning electron microscopy (SEM). When the dosage of RH-NH2 was 50 mg/L, the light transmittance (WT) and corresponding oil removal efficiency (WR) of the separated water were 90.2 ± 1.8% and 94.82 ± 0.95%, respectively, in the emulsion-0.2 (containing 0.2% crude oil). When the dosage was 200 mg/L, the WT and WR values of the emulsion-1 (with 1% crude oil) were 91.9 ± 0.9% and 99.14 ± 0.1%, respectively. In addition, dynamic interfacial tension (IFT), wettability, zeta potential, interfacial activity and adsorption capability of RH-NH2 at the interface were also investigated. The results showed that the IFT values of asphaltene and RH-NH2 (200 mg/L) was 22.58 mN/m and 16.42 mN/m, respectively. The zeta potential of the O/W emulsion was − 37 ± 1.8 mV while that of RH-NH2 was 20.8 ± 1.0 mV, which facilitated the electrostatic neutralization and reduced the electrostatic repulsion between oil droplets. A possible demulsification mechanism was proposed, which indicated that RH-NH2 was amphiphilic, with high interfacial activity and stronger capability to reduce IFT. It migrated rapidly to the oil–water interface and disrupted the interfacial film via synergistic effect of the π-π/n-π interaction, leading to demulsification. RH-NH2 has a potential industrial application due to its low-cost and high demulsification efficiency. [ABSTRACT FROM AUTHOR]

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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]

• OSA-SMDG-stabilized emulsions incorporated with β -carotene had high encapsulation efficiency. • OSA-SMDG-based emulsions improved storage stability of β -carotene. • OSA-SMDG-based emulsions promoted antioxidant activity of β -carotene and protected cells against oxidative stress. • Higher concentration of OSA-SMDG in Pickering emulsion enhanced bioaccessibility of β -carotene. The impact of sugary maize dendrimer-like glucan octenyl succinate (OSA-SMDG) on the storage stability and antioxidant activity of β -carotene (BC)-loaded emulsions as well as bioaccessibility were investigated. The encapsulation efficiency of β -carotene in emulsions containing 3% OSA-SMDG (3OSA-SMDG-BC) or 5% OSA-SMDG (5OSA-SMDG-BC) was 89.6% and 94.9%, respectively. The antioxidant activity of both emulsions was higher than that of pure β -carotene. During simulated digestion, the particle size of emulsions was immediately reduced, whereas zeta-potential was continuously increased in intestinal digestion. After 2 h digestion, the free fatty acids (FFA) release rate of 3OSA-SMDG-BC and 5OSA-SMDG-BC was significantly higher than that of blank emulsion. Bioaccessibility of β -carotene encapsulated in 3OSA-SMDG-BC and 5OSA-SMDG-BC was also significantly higher than that of blank emulsion. FFA release rate and β -carotene bioaccessibility of 5OSA-SMDG-BC were higher than that of 3OSA-SMDG-BC. These results demonstrated that OSA-SMDG could be used to fabricate food-grade O/W Pickering emulsion as a delivery system for bioactive compounds. [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]

[Display omitted] • Lotus leaf treat with a hydrothermal method is used to separate the W/O emulsion. • HLLF can be used in different types of crude oils. • HLLF is natural, low-cost and easily prepared without any chemical modification. • The demulsification efficiency of HLLF is similar to commonly commercial demulsifiers. Looking for efficient, environmentally-friendly, and low-cost demulsifiers for the separation of oil–water emulsion is the goal of oil industry. In current work, natural lotus leaf was used as raw material to prepare a HLLF demulsifier by a simple hydrothermal method without the addition of any chemical reagent. The HLLF demulsifier was utilized to demulsify the water-in-crude oil (W/O) emulsions. Effect of the demulsifier dosage, settling time, temperature and treatment method of HLLF on the demulsification efficiency (DE) was investigated. Encouragingly, the demulsification of the W/O emulsions could occur quickly, and the optimal DE was up to 88.17% with 1000 mg/L of dosage and 90 min of settling time at 70℃. Besides, it could effectively demulsify two types of crude oil emulsions from different oilfields. The possible demulsification mechanism was systematically investigated by scanning electron microscope (SEM), three-phase contact angle (CA), dynamic interfacial tensions (IFT), self-assembly of interfacial film and microscopic analysis. The CA value for HLLF was 81.53° and its IFT was 25.65 mN/m with the dosage of 500 mg/L at room temperature. The prominent demulsification ability of HLLF was attributed to the micro-nano structure on its surface, which may soften or destroy the rigid interfacial film to enhance the film drainage. The finding suggests that HLLF is a promising demulsifier for the separation of W/O emulsion, which exhibits a great application prospect in oil industry. [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]