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To promote the application of lignin in Pickering emulsions, the influences of six lignin particles with different hydrophobicity on the emulsifying and stabilizing performances for oil phases with different polarity to form oil in water Pickering emulsions were investigated. The results showed that the best emulsification performance was achieved when the three-phase (oil–water–lignin particle) contact angle was close to 90°. Alkyl-bridged lignin particles with stronger hydrophobicity have a better emulsification effect on cyclohexane with less polarity, while carboxymethylated lignin particles with stronger hydrophilicity have better emulsification effect on n-heptanol with higher polarity. Furthermore, the stability of Pickering emulsions can be improved by appropriately increasing the surface charge and decreasing the particular size of the lignin particles. [ABSTRACT FROM AUTHOR]

Pour point depressant (PPD) is a crucial addition in the petroleum industry which can significantly enhance the flow properties of crude oil by preventing wax from precipitating out of it. The flow assurance effect of PPD on crude oil is impacted by its molecular structure. As a result, we concentrate on the PPD with various molecular structures, such as carboxyl and benzene rings, to investigate its impact on the flow behavior of crude oil. Then, FTIR and contact angle test were used to describe the characteristics of PPD (SAF-n and SAFS-m). The Karamay crude oil was tested using the following items: pour point, rheology, viscosity, viscoelasticity, and POM. When the crude oil was treated with 1000 ppm SAFS-1, the pour point decreased from 12 to −14 °C and the viscosity decreased from 40.1 to 6.3 pa·s at 0 °C. Meanwhile, the results show that the more variety polar groups PPD has, the more its dispersion increases and the stronger its interactions with crude oil are when its molar ratio of non-polar groups are suitable. These effects may be caused by the PPD changing the crystallization characteristics of wax and the aggregate state of resin and asphalt. [ABSTRACT FROM AUTHOR]

AbstractAs an important inorganic antibacterial nanomaterial, zinc oxide nanoparticles (ZnO NPs) have been widely used in biomedical fields. However, the poor dispersion and potential toxicity greatly limit its application. Surface modification is an effective method to improve the dispersion and biocompatibility of ZnO NPs. In this work, ε-polylysine (ε-PL) was grafted on the surface of ZnO NPs via the combination of mussel inspired method and “Michael addition” reaction. The results showed that the ε-PL grafted ZnO (ZnO@ε-PL) could disperse stably in water more than 72 h, demonstrating ε-PL greatly improves the dispersion of ZnO NPs. Furthermore, the cells viability of ZnO@ε-PL at high concentrations (500 μg/mL) was 143.05 ± 12.63%, indicating that the biocompatibility of ZnO@ε-PL is much better than that of ZnO NPs. This study proposed a feasible and effective strategy to improve the dispersion and biocompatibility of ZnO NPs, which may expand the application of ZnO NPs in the biological field. [ABSTRACT FROM AUTHOR]

Oil-based foam stabilized by dispersed asphaltene is potential in the oil recovery process of water-sensitive formations. But asphaltenes are prone to aggregate, which jeopardizes the stability of the foam. This paper investigated the effect of different VO79 (model asphaltene compound violanthrone-79) systems on the performance of oil-based foams through surface tension and foaming tests. And simulations were performed to investigate the microscopic mechanism of ODA (octadecyl amine) and Span20 (sorbitan monolaurate) on the dispersion effect of VO79 and the effect of their mixtures on the interfacial film formation. The experimental results showed that the mixed system of ODA, Span20, and VO79 significantly enhances the performance of the oil-based foam. According to simulative results, ODA and Span20 blending are able to form ODA: Span20 molecular pairs, inhibiting the aggregation of model asphaltenes. The blend of ODA, Span20, and VO79 tends to form a ternary supramolecular complex, assembling into a dense and stretchable interfacial film. The synergistic effect generated by the ternary blends is capable of optimizing the performance of oil-based foams. [ABSTRACT FROM AUTHOR]

Oil-based foam has become a research hotspot in petroleum industry, whose stability plays a key role in the application. The employment of oil-based foam prevents the damage to water-sensitive reservoir. This paper focuses on the stabilization of oil-based foam by improving the viscoelasticity of foam film and the effect study of polymer-surfactant. The Polydimethylsiloxane (PDMS) and Natural rubber (NR) are employed to stabilize oil-based foam, and the comprehensive properties of foam which created by air flow method are evaluated by FCI. Besides, the behavior of interfacial adsorption foam film is analyzed through rheological study and molecular dynamics (MD) simulation. According to the results, the oil-based foam volume increases to 150 mL and the half-life time is extended to 140 s with the combination of NR and PDMS. It is ascribed that the synergistic effect of NR and PDMS molecules. The NR molecules, which are stretched and crimped corresponding to the change of external force, begin to move toward the interface after blending with PDMS to improve the viscoelasticity of the foam film. [ABSTRACT FROM AUTHOR]

The efficient separation of emulsified oily wastewater is urgently needed and remains a worldwide challenge. However, the preparation of underwater superoleophobic materials still suffer from complicated process control, special equipment and expensive reagents, which further restricts the large-scale application of such materials. Herein, one-step constructing of underwater superoleophobic beds is introduced for highly efficient gravity-directed separation of various oil-in-water emulsions. Importantly, this study simplifies the fabrication process of underwater superoleophobic materials. It's worth noting that the strategy can achieve the effective separation of a range of oil-in-water emulsions by only requires simple accumulation of hydrophilic materials. More importantly, the underwater superoleophobic sandwich-structured beds still maintain the separation efficiency more than 99.2% after 10 cycles. In addition, this strategy is suitable for a variety of hydrophilic materials, which provides new perspectives for fabrication of novel oil-water emulsion-separating materials. One-step constructing of underwater superoleophobic bed was used for high efficiency separation of oil-in-water emulsions. [ABSTRACT FROM AUTHOR]

Abstract Given the low plugging success rate of existing plugging agents in oilfield applications, this study proposed a new selective plugging agent system (SA-1-S) with a high plugging efficiency, which dissolves in oil and releases oil flow channels under formation temperature conditions. Being insoluble in water and acid, it blocks water flow channels. In particular, at ambient temperature of 25 °C and reservoir temperature of 65 °C, the dissolution rate of SA-1-S particles in formation crude oil, kerosene, and diesel oil exceeded 96%, being suitable for formations at temperatures below 120 °C∼130 °C. The proposed agent’s plugging rate exceeded 90% on cores and 80% under reverse kerosene action; this rate dropped under forward scouring by 2.01 ∼ 3.21%. The selective water plugging agent proposed in this paper has application prospects in improving the oil recovery in high water-bearing oil wells. [ABSTRACT FROM AUTHOR]

Concentrated suspensions were prepared from submicron cerium oxide particles, and particle size distribution (PSD) and zeta potential of the particles were researched by ultrasonic attenuation technology and electroacoustic theory. The influences of particle concentration, base solution and pH value on particle dispersion behavior in suspensions were analyzed. It was found that for suspensions with concentration from 10 wt% to 30 wt%, the ceria particles were dispersed most sufficiently in the suspensions with sodium hexametaphosphate (SHP), while for suspensions with concentration 40 wt%, the particles were dispersed most sufficiently in the suspensions with deionized water (DIW) only. On the other hand, the particles agglomerated most remarkably in all suspensions with sodium carboxymethyl cellulose (CMC), and they had the lowest value of zeta potential. It was deduced that higher zeta potential could be helpful for particle dispersion in these concentrated suspensions, while non-DLVO interaction and dispersing process might play important roles too. [ABSTRACT FROM AUTHOR]

The purpose of this work was to analyze and evaluate the functional properties of a new nanoemulsion that contained cordycepin. Droplet size and distribution were measured, and the stability of the nanoemulsion in different storage conditions was evaluated. We also tested skin irritation caused by the nanoemulsion, cordycepin stability in the nanoemulsion, anti-aging effect, and microbial challenge. The nanoemulsion was homogeneous with proper dispersion stability, and cordycepin was stable for eight months within the cosmetic nanoemulsion. The nanoemulsion did not irritate human hand and face skin, and the cosmetic nanoemulsion was effective in preventing microbial contamination of the product during use and storage. The new nanoemulsion containing cordycepin satisfied provisions of the 2015 Safety and Technical Standards for Cosmetics of the Ministry of Health, People's Republic of China. [ABSTRACT FROM AUTHOR]

The hydrophilic surface and developed pore structure restricted the application of abundant low rank coals (LRC) for the preparation of coal water slurry (CWS) with high concentration. In this work, emulsified asphalt was applied as an effective and low cost modifier to modify coal surface and improve the slurry making performance of LRC. The successful modification was verified by various technologies, such as chemical titration, X-ray photoelectron spectroscopy (XPS) and Zeta potential measurements. The results revealed that the oxygen containing groups located at LRC surface were covered by emulsified asphalt, which further caused the decrease of Zeta potential. The influence of modification on wettability of coal was also evaluated by contact angle and moisture re-adsorption. It showed that the hydrophobicity of LRC significantly increased, which is accompanied with the reduction of inherent moisture. Besides, the results of nitrogen adsorption and scanning electron microscope (SEM) verified that the hydrophobic layer formed by emulsified asphalt blocked the pores of LRC. The modified LRC also exhibited better adsorption ability to the widely used anionic dispersant naphthalene sulfonate formaldehyde condensate (NSF) than that of raw coal (RC) and microwave dehydration coal (MDC). Anyhow, modified LRC possessed the characteristics as high rank coal. Afterwards, modified coal was applied to prepare CWS. The results showed that CWS prepared by modified LRC exhibited superior slurry making performance as compared to RC and MDC. The surface modification reduced the inherent moisture and promoted the adsorption of dispersant, which increased the free water amount and enhanced electrostatic repulsion and steric hindrance among coal particles. Accordingly, the maximum concentration for CWS increased, and the static stability enhanced. [ABSTRACT FROM AUTHOR]

In view of problem that nanoscale zero-valent (nZVI) is easy to agglomerate and deactivate in the process of wastewater treatment, a styrene-based ion exchange resin D201 is selected as the carrier to load it. D201-loaded nZVI (D201@nZVI) was applied to treat simulated Cr(VI) wastewater. Receiving the effect and influence of electrostatic attraction, Cr(VI) will attach to D201@nZVI, partly reduced to Cr(III) by nZVI to form CrxFe1−x(OH)3 co-precipitation. D201@nZVI shows good treatment capacity of a wide pH range, and excellent regeneration performance. The removal rate and maximum adsorption amounts of 50 mg L−1 Cr(VI) reached 100% and 123.14 mg g−1, respectively. D201@nZVI has promising potential to be applied in situ groundwater remediation. [ABSTRACT FROM AUTHOR]

A chemical-modified biochar material (MGBC) derived from Brassica straw was synthesized using magnetic-gelatin as a modification reagent and employed to remove Cr(VI) from aqueous solution. MGBC before and after reacted with Cr(VI) was characterized by FT-IR, XRD, SEM-EDS, XPS, and VSM (Vibrating Sample Magnetometer). Characterization results indicated that the underlying mechanisms of remove Cr(VI) by MGBC were primarily relied on the chelation of functional groups and reduction-coupled surface precipitation. Additionally, the effect of pH, initial Cr(VI) concentration, adsorption time, ionic strength, and coexisting ions on adsorption capacity of MGBC were evaluated and optimized by batch adsorption experiments. All findings illustrated that the maximum adsorption capacity of MGBC for Cr(VI) was 434.85 mg/g obtained at pH = 1 and the adsorption process was highly dependent on pH, and well consistent with Freundlich model and Pseudo-second-order (PSO) model. Furthermore, approximately 72% of equilibrium adsorption capacity for Cr(VI) was still possessed by MGBC under a considerable degree of ionic strength or a given concentration of coexisting ions, which demonstrated that MGBC equipped with strong selective adsorption ability and anti-jamming capability in practical wastewater. All results herein manifested that MGBC equipped with favorable practicability and reusability, which could serve as a low-cost and high-efficiency adsorbent to remove Cr(VI) from complex water environment. [ABSTRACT FROM AUTHOR]

Oily wastewater causes a lot of environment problems and draws wide attention. In this paper, titanium modified multi-walled carbon nanotubes (CNTs/TiO2) for the treatment of oily wastewater were synthesized using in situ sol-gel methods. Fourier transform infrared spectroscopy (FT-IR) and X-ray diffraction (XRD) were employed to characterize the structure and composition of CNTs/TiO2. Also, scanning electron microscope (SEM) and transmission electron microscope (TEM) showed that TiO2 was evenly distributed in carbon nanotubes (CNTs) to induce a good synergistic effect. After the oily wastewater was treated with 400 mg/L of CNTs/TiO2 at room temperature for 30 min, the light transmittance of the aqueous phase was 89.7%. Furthermore, the composites with good interfacial activity could be reused at least five times. The combination of dynamic interfacial tension measurements, interfacial activity, interfacial film assemble and optical microscope was employed to investigate the demulsification mechanism. [ABSTRACT FROM AUTHOR]

This work aims to establish the relationship between the morphology and rheology changes affected by the addition of Flat-rheology modifier (FRM) to organoclay (OC)/white oil dispersions between 2 and 65 °C to analyze the flat-rheology formation mechanism in nonaqueous drilling fluids. The FRM used in this work is poly(diethylenetriamine dimer acid amide), and the OC is organo-montmorillonite. Temperature-controlled rheological tests confirmed that FRM addition to dispersions with low OC loadings (lower than 3.0 wt%) results in a relatively constant gel strength from 2 to 65 °C. This could be explained by the morphology variations in the dispersions generated by the FRM. Based on macroscopic settlement, particle size distribution, optical microscopy, transmission electron microscopy (TEM) and wide-angle X-ray scattering (WAXS) results, FRM molecules were inserted into and enlarged the interlayer space between OC platelets, thus reducing the particle size and improving the dispersion stability. Subsequently, the original card house network formed by OC particles was destroyed, and a new network with a larger volume fraction was formed by the highly dispersed platelets and FRM molecules. The increase in network volume fraction and extension of FRM molecular carbon chains with increasing temperature inhibit network strength deterioration. As a result, the rheological properties at 65 °C remained similar to those at 2 °C, thereby forming a flat rheology. The interaction mechanism of poly diethylenetriamine dimer acid amide and organo- montmorillonite in forming flat-rheology between 2 and 65 °C. [ABSTRACT FROM AUTHOR]

In deep well drilling, the filtration-loss reducer remarkably impacted the rheological property of water-based drilling fluids at high temperature and salinity, causing serious problems during the drilling process. In this work, a combination of low molecular weight amphoteric copolymer and bentonite clay was exploited to tackle these issues due to their relatively different thermal-saline-properties dependence. In detail, a novel amphoteric tetramer (AB-47) of N,N-dimethylacrylamide (DMAm), 2-acrylamide-2-methylpropanesulfonic acid (AMPS), diallyl dimethylammonium chloride (DMDAAC), and N-vinylpyrrolidone (NVP) was prepared by free-radical copolymerization technique under optimal conditions. And the molecular structure of AB-47 was evidenced by FT-IR, 1H NMR, and elemental analysis. The filtration and rheological performance of AB-47 in low solid-phase water-based mud (LSWBM) were examined in comparison with Driscal D before and after a 16 h aging at 230 °C according to the American Petroleum Institute (API) standard. Results indicated that, only 1% AB-47 could not only control an API filtration loss volume of 8.9 mL but also the change rate of main rheological parameters were found to be more stable while parameters of Driscal D containing mud not only varied dramatically but also an API filtration loss of 30 mL could be maintained under identical conditions. Although the contamination with NaCl affected both muds properties, AB-47 could still exhibit higher performance. Therefore, the relative stability of AB-47 containing mud with respect to the chemical environment could be achieved through the strong synergistic interactions between AB-47 and bentonite particles, which were examined through particle size distribution, zeta potential and scanning electron microscopic. [ABSTRACT FROM AUTHOR]

Cork is a renewable and biodegradable raw material, which was directly stripped from the periderm of oak bark. The natural amphiphilic chemical composition endowed its pristine surface with hydrophobicity and superoleophilicity in air. Based on the wettability of pristine cork, a stable superhydrophilic and superoleophilic cork membrane without any coating was fabricated via a facile, low-cost, and eco-friendly ethanol- and H2O2-treating process. The superamphiphilic treated membrane exhibited underwater superoleophobicity or underoil superhydrophobicity just by prewetting it with water or oil. This superamphiphilicity of the obtained membrane, combined with its natural permeability of tracheids, plasmodesmata and capillaries, enabled it to separate heavy oil from water or separate water from light oil. Furthermore, without using any continuous external stimulus, a good reversible switching between underwater superoleophobicity and underoil superhydrophobicity could be achieved simply by drying and washing alternately. With such superwettability, the membrane could selectively separate oil/water mixtures with high separation efficiency over multiple cycles solely driven by gravity. Moreover, the membrane could maintain superamphiphilicity in air and superamphiphobicity under liquids after scratching by a penknife or rubbing by a sandpaper. This simple but effective strategy will inspire the design and fabrication of other plant membranes for practical applications in oil/water separation. [ABSTRACT FROM AUTHOR]

A series of anion-nonionic hyperbranched surfactants HPSA were prepared by grafting the N-lauryl-monoamido sulfosuccinic acid onto hydroxyl-terminated hyperbranched polyamide ester (HP). The optimum grafting condition was obtained by single-factor experiments when the mole ratio of HP and N-lauryl-monoamido sulfosuccinic acid was 1:5. The molecular structure of HPSA-5 were characterized by Fourier transform infrared spectroscopy, proton nuclear magnetic resonance spectroscopy and gel permeation chromatograph. Furthermore, the wettability, surface activity and emulsifying ability of the prepared surfactant were studied. The results showed that HPSA-5 solution had good potential on change of wettability. Surface activity studies showed that HPSA-5 was temperature-resistant and salt-tolerant capacity of 140 °C and ρ(NaCl) = 2 × 105 mg/L, ρ(CaCl2) = 1.5 × 104 mg/L, respectively. In the heat aging experiment (under the temperature of 120 °C and the NaCl of 105 mg/L for 12 hours), the surface tension of HPSA-5 were almost unchanged. The salt tolerence of 0.3 g/L HPSA-5 was superior to 0.3 g/L SDS and 0.3 g/L OP-10 at the ability of emulsifying Tahe crude oil (China, Xinjiang) at 120 °C. The result of the sandpack model crude oil displacement experiments showed that 1.5 g/L HPSA-5 could further increase the crude oil recovery to 10.27%, compared with 6.44% crude oil recovery for 0.6 g/LSDS + 0.9 g/L OP-10 after water flooding. [ABSTRACT FROM AUTHOR]

For the development of national industry green environmental protection, the use of zinc dialkyl dithiophosphate (ZDDP) should be reduced in the process of mechanical lubrication, two novel borate esters, SS-(5-disulfanyl-1,3,4-thiadiazol-2-yl) O-(6-stearoyl-1,3,6,2-dioxazaborocan-2-yl) carbono(dithioperoxoate) (BNSD) and 6-stearoyl-1,3,6,2-dioxazaborocan-2-yl stearate (BNCD), were synthesized and characterized by FT-IR and TGA. Tribological performance of ZDDP, BNSD and BNCD as a multifunctional additive in synthetic ester base oil were investigated under different loads using a MR-S10 four-ball and MFT-3000 friction and wear test machine. A scanning electron microscope and laser scanning confocal microscope were used to observe worn scar surface morphology of the balls. The chemical compositions of worn surface were analyzed by X-ray photoelectron spectroscopy and the tribofilm of the worn surface was observed by transmission electron microscope. The TGA curves showed that BNSD and BNCD had a better thermal stability than ZDDP. BNSD exhibits excellent anti-wear and friction-reducing properties, the PB value is increase to 784 N when the optimized concentration is 0.3% the minimum WSD of BNSD-based lubricant is approximately 0.52 mm and decreased by 35% compared with the base oil. A protective tribofilm of the ball steel was analyzed by XPS and TEM, which revealed that B2O3 and Fe2B constitute the triboilm and about 5 nm. Therefore, BNSD could be a candidate as anti-wear and friction-reducing agent in lubricants instead of ZDDP. [ABSTRACT FROM AUTHOR]

N-lauroyl-L-Valine sodium (NLLVS) was synthesized and characterized by FT-IR, 1H-NMR spectrometry. Surface and interface tension were measured by wilhelmy plate and spinning drop method. The effects of surfactant concentration, salt, polymer and mixed surfactant on interfacial tension were studied in detail. The critical micelle concentration (cmc) was 6 × 10−3 mol/L and cmcoil was 8 × 10−3 mol/L. The equilibrium interfacial tension (IFTequ) first decreased and then increased with NLLVS increasing. Mixed salts were less effective at reducing interfacial tension than NaCl and CaCl2, while the higher concentration of NaCl was needed to obtain the same IFT as added CaCl2 and NaCl/CaCl2. The lowest IFTequ obtained at the NaCl concentration of 10% when the ratio of NLLVS and Alkyl polyoxypropylene polyoxyethylene ether sulfate (P12) was 2:8. Polyacrylamide was disadvantage to reduce IFT, while polyacrylamide was arranged more tightly by NLLVS. Morphology of HPAM with different concentrations of NLLVS (a) 0 mol/L (b) 10−4 mol/L (c) 10−3 mol/L (d) 10−2 mol/L (e) 10−1 mol/L [ABSTRACT FROM AUTHOR]

Uniform and highly dispersed magnesium hydroxide nanoparticles were synthesized in cetyltrimethyl ammonium bromide/cyclohexane/isopropanol/water microemulsion. The effect of different experimental conditions on particle size was investigated and the control mechanism was discussed. The results indicated that the R value (R= [water]/[surfactant]) and the dosage of isopropanol could control the particle size by varying the "water droplet" size in microemulsion; the Mg2+ concentration and the mole ratio of Mg2+ to OH− could fine tune the particle size by varying the solution supersaturation in water droplet. The dosage of isopropanol had the greatest influence on particle size and could control the particle size in the range of 53.66 to 110.06 nm. Our evidences demonstrate that the magnesium hydroxide particle size can be precisely controlled and could realize better application value. [ABSTRACT FROM AUTHOR]

The interaction between biological surfactant sodium deoxycholate (NaDC) and nonionic surfactants polyoxyethylene (n) nonylphenol ether (NPn) for the formation of micelles in aqueous solution were investigated. Surface tension, interfacial dilational viscoelasticity, and transmission electron microscopy (TEM) were characterized to systematically study the interaction between NaDC and NPn in buffer solution. At last, the mechanism of the interaction between NPn and NaDC were analyzed. The surface tension results show that the interaction between NaDC and NPn was displayed synergism action. The composition of the mixed systems has been estimated on account of the regular solution theory, Clint's equation, Rubingh theory and Rosen theory. The surface dilational rheology provided abundant effective information on the feature of adsorbed layers. From the oscillating barrier measurements, the peak values of the dilational modulus moved to lower concentrations in NaDC/NPn binary system compared to single surfactant. The dilational elasticity of the binary system decreased distinctly on the basis of the rigid structure of NaDC. The interaction of these two substances was proved directly by TEM images, that the boundaries of the aggregates are clearer due to the protection of NPn molecules. The new complex systems have potential application in environmental protection. Schematic illustration of the aggregation in NPn/NaDC mixed systems and concentration increased from left to right. [ABSTRACT FROM AUTHOR]

In this paper, a selective nickel ions chelating adsorbents (Ni-CMCS) were prepared based on carboxymethyl chitosan by ion imprinting technique. Scanning electron microscope (SEM), Fourier transform infrared spectroscopy (FT-IR) and X-ray photoelectron spectroscopy (XPS) were used to investigate their physicochemical properties. Brunauer-Emmett-Teller (BET) analysis showed that the BET surface area of Ni-CMCS had a significant increase after ion imprinting process. The effects of pH value, contact time and initial concentration of Ni(II) were studied. The adsorption kinetics were investigated, which indicated that Ni-CMCS was better fitted with pseudo-second-order kinetic model (R2 = 0.9991) with film diffusion process as rate controlling step. The adsorption isotherms study indicated that Langmuir model matched better with the experimental data for Ni-CMCS (R2 = 0.9617). Besides, the maximum adsorption capacity calculated from the Langmuir equation was 82.78 mg g−1. Moreover, the selectivity experiment suggested that Ni-CMCS had good selectivity in the presence of Co(II), Mn(II), or Cd(II). After used four cycles, Ni-CMCS kept great adsorption capacity. [ABSTRACT FROM AUTHOR]

AbstractBiocompatible high internal phase emulsions (HIPEs) have attracted much attention in food and cosmetics due to their unique properties, such as adjustable viscoelasticity, high nutrient load, and long shelf life. Herein, we report an olive oil-in-water high internal phase Pickering emulsion (HIPE) stabilized solely by bare hydroxyapatite (HA) nanoparticles. Compared with other HIPEs, the HIPEs stabilized by HA nanoparticles could be obtained through a one-step emulsification method without chemical modification or other chemical additives. The increase of HA concentration (≥ 0.5 wt%) resulted in increases in both the storage modulus and loss modulus of the HIPEs, indicating the particle network plays an essential role in the HIPEs gel strength. After increasing the oil phase fraction from 80% to 90%, the viscosity of the HIPEs increased from 8316 to 13855 Pa⋅s (shear rate 0.004 s−1) and exhibited as a pseudoplastic fluid. The effect of oil type on the HIPEs was also investigated. The HA nanoparticles may interact with the olefin and carbonyl groups of olive oil, forming interfacial-active particles to stabilize the HIPEs. This method is universal as it occurs with other natural oils (soybean, sunflower, and fish oil), which may have various applications in food, cosmetics, and functional material fields. [ABSTRACT FROM AUTHOR]

Phase separation behavior is a critical character in determining the usefulness of a solvent extraction system in hydrometallurgy. A survey of the synergistic mixture containing dinonylnaphthalene sulfonic acid (HDNNS) and 2-ethylhexly 4-pyridinecarboxylate ester (4PC) for the extraction of copper or nickel from acidic single metal sulfate solution has been carried out to suggest how the physicochemical properties (density, viscosity and interfacial tension) and the morphology of the reverse micelles in the loaded organic phase affect the phase separation behavior in this paper. The specific settling rates (SSR), physicochemical properties, metal concentration and the excess water uptake (the content of water solubilized into the water pool of the reverse micelles) in the loaded organic phase during the extraction of Cu(II)/Ni(II) have been measured. The results show that the most effective parameters affecting the phase separation behavior are the viscosity and the excess water uptake of the loaded organic phase. We assume that the deceleration of the SSR is mainly due to the apparent increase of these two parameters or in a microscopic view, the apparent change of the morphology of the reverse micelles in the loaded organic phase. The small angle X-ray scattering (SAXS) results provide a direct evidence of such microstructural changes and well supports our assumption. [ABSTRACT FROM AUTHOR]

Water-in-oil emulsion separation through a fibrous media bed is a complex process in industries. In this article, in order to select the optimal fibrous material for the separation of water-oil emulsion, three types of commercial fibers as fibrous beds were used to separate water from diesel oil. Based on the principle of orthogonal experimental design, a series of experiments were performed to investigate the effect of such parameters as bed porosity (0.77-0.89), bed length (100-400 mm) and settlement length (120-480 mm) on the separation efficiency and the superficial velocity, and then three parameters were optimized to achieve good separation performance. The experiment showed that the separation efficiency could reach 77% and the flow velocity could reach 30 m/h under the optimal bed structure and stable working conditions. The results of this paper could provide basic designing reference for the industrial application of fibrous bed coalescer. [ABSTRACT FROM AUTHOR]

Physical and chemical modifications were made on the surface of the aluminum sheet to change the surface properties and superhydrophobic–hydrophilic wettability gradient surface was made on the perspex surface by using microstructure-pattering technique and self-assembled-monolayer method. By using high-speed video camera system and optical tensiometer, this paper discusses the influence of special surfaces with different wettability on spreading and motion of water, oil, and W/O emulsion droplets both experimentally and theoretically. In addition, the paper also discusses the influence of the superhydrophobic–hydrophilic wettability gradient on fluidity of W/O emulsion droplets and the coalescence process of droplets. The results showed that the contact angle of W/O emulsion droplets on the modified surfaces was related to the water and oil distribution at the three-phase line. On the wettability gradient surface, the droplet moved spontaneously when the droplet was located at the junction of the gradient. A quasi-steady theoretical model was used to analyze the driving and resistant forces acting on a droplet to improve the understanding of the self-transport behavior of the droplets. [ABSTRACT FROM AUTHOR]

In the present study, cationic xanthan gum (CXG) was synthesized to enhance the rheological property of xanthan gum (XG) by attaching quaternary amine groups to the backbone of XG. The efficacy of the substitution was confirmed by FT-IR spectra and13C NMR. The surface morphology was changed considerably as demonstrated by SEM. The examined rheological properties of XG and CXG include steady-state and dynamic rheological properties. The results show that quaternary amine groups are successfully grafted onto the XG molecule. Apparent viscosity, storage modulus, and loss modulus of CXG solutions are greater than those of XG solutions under the same conditions. It is moreover found that apparent viscosity and viscoelasticity increase with the degree of substitution. The data indicate that the modified XG has much better heat resistance. [ABSTRACT FROM PUBLISHER]

Three types of multiple emulsions were prepared with lecithin. The morphology, stability, and rheological properties of the three types of W/O/W multiple emulsions were evaluated. The formulation factors, including salts and aliphatic alcohol, were further examined. The three types of multiple emulsions were formed by different emulsifiers. An excellent multiple emulsion occurred with 2 wt% lecithin concentration, stabilized by 0.05 wt% NaCl. All multiple emulsions showed shear-thinning behavior, i.e., the apparent viscosity decreased with the increase of the shear rate. With the high concentration of lecithin, the multiple emulsions exhibited the highest viscosity at low shear rate and had higher storage modulus (G′) and the loss modulus (G″). This study was conducted to reveal that different types of multiple emulsions can be formed with lecithin, and that the stability and rheological properties were different with different types of multiple emulsions. [ABSTRACT FROM AUTHOR]

AbstractDuring the drilling process, the hydration and expansion of shale are one of the main reasons for wellbore instability, which can lead to stuck drilling and economic losses. A novel shale inhibitor (ADG) was successfully synthesized by thermal polymerization using Acrylamide (AM), Dimethyl diallyl ammonium chloride (DMDAAC) and Graphene as raw materials, Ammonium persulfate, and Sodium bisulfite as initiators. In order to study the structural characteristics of ADG, Fourier transform infrared spectroscopy (FT-IR), X-ray diffraction (XRD), Thermogravimetric loss test (TG), and Scanning electron microscopy (SEM) test were conducted. Simultaneously, linear swelling test, mud making test, sedimentation test, contact angle test, and montmorillonite (MMT) impregnation test were conducted to evaluate its inhibitory performance. ADG can reduce the expansion height of bentonite test blocks from 6.4 mm to 2.06 mm. After adding ADG, the settling speed can be effectively accelerated, with a settling time of only 15 min and a settling height as low as 60 mm. SEM analysis revealed that ADG had a regular flake-like structure. Compared to conventional shale inhibitors, ADG can increase the contact angle of bentonite test blocks from 26.8° to 46.8°, improving their hydrophobicity. Mechanistic studies suggested that ADG molecules could adsorb on the shale surface and block surface pores, reducing the contact area between shale and water. Additionally, small ADG molecules could penetrate the pore interiors and form hydrophobic films. The dual mechanism of ADG, inhibiting hydration and providing physical blockage, further demonstrated its excellent inhibitory performance. [ABSTRACT FROM AUTHOR]

Lignin-based dye dispersants have aroused an increasing interest due to their environment-friendly properties. In this research, the quaternized lignin-based dye dispersant (QLD) was prepared using alkali lignin from masson pine sulfate pulping liquor as raw materials by chemical modification, that is, sulfonation and quaternization. The structure and performance characterization of alkali lignin and QLD were studied. The analyses indicated that the structural unit of alkali lignin contained more G type and S type. Additionally, it was also proved that QLD contained quaternary ammonium group, amine group, and sulfonic group, which could improve the dispersion performance and thermostability of QLD. The results of thermogravimetric (TG) concluded that the dispersion performance and thermostability of QLD prevailed over alkali lignin. Compared with the contact angle of water, alkali lignin, and QLD with dye, the contact angle of QLD was much better than water and alkali lignin, indicating that the hydrophilicity and dispersion performance of QLD were superior to water and alkali lignin in Vat Olive T. [ABSTRACT FROM PUBLISHER]

Biochar (BC) has been widely used as a low-cost adsorbent for the removal of contaminants from water and soil. However, the adsorption ability of BC towards heavy metal oxyanions (e.g., Cr(VI)) is relatively low due to the negatively charged surface of BC. In this study, pristine BC was impregnated with Fe3+to improve its Cr(VI) adsorption capability. Fe3+-impregnated BC (Fe3+-BC) was successfully synthesized by a simple impregnation method and used for the removal of Cr(VI) from aqueous solution. Various factors affecting the adsorption, such as impregnation ratio, pH, adsorbent dosage, contact time, temperature, and the presence of humic acid, were investigated in detail. Results showed that Fe3+-BC had strong adsorption ability to Cr(VI) with a maximum adsorption capacity of 197.80 mg/g, which were not only significantly higher than that of the pristine BC, but also were superior to many previously reported adsorbents. It was favorable for Cr(VI) adsorption under the condition of acidic and high temperature. The adsorption data obeyed Sips and Langmuir isotherms and the kinetic data were well described by the pseudo-first-order kinetic model. The results herein revealed that the Fe3+-impregnated BC had a good potential as a highly efficient material for adsorption of Cr(VI) from aqueous solution. [ABSTRACT FROM PUBLISHER]

A new type of hyper-dispersant was designed and successfully synthesized by free radical solution polymerization method to improve the dispersing performance of nano-copper in base oil. The microstructures of the product were characterized by means of x-ray diffraction (XRD), Fourier transformation infrared spectrometry (FTIR), and transmission electron microscopy (TEM). The hyper-dispersant as modifier was chemically bonded to nano-copper via strong chemical interaction. The influences of nano-copper modified by hyper-dispersant on the lipophilic degree and wettability were investigated. It was found that the modified nano-copper had the best dispersion performance in base oil, and the optimum amount of hyper-dispersant was 8 wt%. The tribological behavior showed that modified copper nanoparticles possessed excellent friction-reduction and antiwear properties. Meanwhile, the extreme pressure property of the base oil was also improved strikingly. And the maximum non-seizure load (PB) of base oil was improved by 27% at the point of 0.1 wt%. [ABSTRACT FROM PUBLISHER]

Transition from oil-in-water (O/W) emulsions to water-in-oil (W/O) emulsions and its action on enhanced oil recovery was investigated by viscosity, morphology, and simulated flooding experiments. This transition can be realized by increasing the volume ratio of oil to water or decreasing the emulsifier concentration. At a mass concentration of 0.3 wt%, the self-developed emulsifier FJ-1 mainly forms O/W emulsions at a volume ratio (oil to water) of 1:1. The emulsions behave as O/W emulsions with a low viscosity when the volume ratio of oil to water is below 2:1. Above 2:1, increasing volume ratio leads to the O/W emulsions transferring into W/O emulsions with high viscosity. For example, at a volume fraction of 4:1, the viscosity of W/O emulsions reaches 229.1 mPa · s, and separated water can hardly be detected. Transition from O/W emulsions to W/O emulsions with high viscosity can also be realized by decreasing the concentration of emulsifier to 0.05 wt% or lower at a volume ratio of 1:1. These may be the critical factors leading to transition from O/W emulsions to W/O emulsions at core conditions. Simulated flooding experiments show that emulsifier fluids can act as an in situ mobility improver and make an improvement of oil recovery even by 20.4%. The results indicate that the water-in-crude-oil emulsions possess great potential in enhancing oil recovery. [ABSTRACT FROM PUBLISHER]

Wormlike micellar octadecyl trimethyl ammonium chloride (OTAC) solution is a self-assembled fracturing fluid used to carry proppants into fractures in oil recovery. Slow settling velocity of proppant is desirably resulted from the viscoelastic drag with low viscosity of fracturing fluids for fracturing work. Steel spheres, as a substitute for proppants, fall into three semi-dilute OTAC solutions. The steady rheology demonstrates that OTAC solutions are divided into shear-thickening and shear-thinning regimes by the critical shear rate. The applied steel spheres always lie in the shear-thickening regime of the 2.8 wt% OTAC solution with aggregated micelles as their characteristic shear rates are less than the critical shear rate of the solution. Strong shear-thickening viscous drag results in lower settling velocity of steel spheres. Most of the applied steel spheres, on the other hand, lie in the shear-thinning regime of the 4 wt% OTAC solution with orientated micelles. Although the latter solution has small dissipation coefficient, high Weissenberg number, and consequently high elastic effect, the shear-thinning viscosity results in higher settling velocity of steel spheres. [ABSTRACT FROM PUBLISHER]

Most of the high permeability reservoirs in the Daqing Oil Field have been conducted by water flooding and polymer flooding. Further development of such mature reservoirs has become a big challenge due to highly dispersed residual oil. Foam flooding, as a candidate enhanced oil recovery (EOR) technique, has been proposed. In this article, EOR evaluation of CO2foam flooding after polymer flooding has been conducted on homogeneous sandpack cores flooding tests at the reservoirs condition. Results indicated that CO2foam flooding could enhance considerable oil recovery, even if the oil recovery occurs after polymer flooding. It was also found that higher quality foam with higher pressure gradient could improve larger swept volume and, thus, recovered more residual oil than lower quality foam did. The influence of both the injection strategy and solubility of CO2in brine on EOR of CO2foam flooding was also studied. [ABSTRACT FROM AUTHOR]

Particles-stabilized foams have received more attention in recent years due to their specific characteristics and advantages in contrast to conventional foams which were stabilized with surfactants. However, the rheology of particles-stabilized foam in consolidated cores was rarely studied. To investigate the feasibility of the particles-stabilized foam application in enhanced oil recovery, the blocking ability and flowing characteristics of foam stabilized with clay particles were investigated by using experimental cores. To do this, the foam resistance factor was studied as an index in this article. The effects of foam quality (gas velocity divided by total velocity), injection rate of foam, and the permeability of cores on the blocking ability of foams were investigated. Results showed that the blocking ability reached the peak value at the foam quality of 0.74. This indicated effective blocking ability as conventional foams performed in porous media. Moreover, the foams block the channels more effectively in high permeability cores, compared with low permeability ones. Finally, foams displayed shear-thinning property in porous media as injection rate increased. [ABSTRACT FROM AUTHOR]

The enhanced oil recovery (EOR) results of foam flooding depend largely on the stability of foam flow within porous reservoirs. To stabilize foams, polymers such as partially hydrolyzed polyacrylamide are often introduced into the foaming agent. However, particles-stabilized foams have been paid more attentions in recent years. To investigate the better stabilizer for foam application in EOR, experimental stability comparison between polymer-stabilized foams and clay particles-stabilized foams was investigated. To do this, the static stability of bulk foams was studied by half-life of foams and rheological behavior of foaming agent solution. The dynamic stability of two types of compressed foams in porous media was then compared with blocking ability. Results showed that particles-stabilized bulk foams were more stable than polymer-stabilized bulk foams, and the viscoelasticity of surfactant-particles solution was higher. Moreover, blocking ability of particles-stabilized foams was also better than that of polymer-stabilized ones. [ABSTRACT FROM AUTHOR]

The physicochemical properties of coix seed oil (CSO) liposomes prepared by five different methods were evaluated for morphology, encapsulating efficiency, particle size, storage stability, and in vitro release. The different preparation methods resulted in several types of vesicles with different properties. The type of vesicles was closely related to leakage pattern, which affected the storage stability and in vitro release profiles. Ethanol injection method was the best choice for preparing safe and stable liposomes with controlled release. The release mechanisms might account for the diffusion of CSO, and Higuchi was the most suitable model for liposomes stored at high temperature or released in simulated intestinal fluid (SIF). [ABSTRACT FROM PUBLISHER]

The extensional viscoelasticity modulus and conductivity of liquid films and stability of bulk foams were investigated respectively. The effects of sinusoidal exciting frequency, polymer type, and polymer concentration on liquid film viscoelasticity modulus were systematically discussed. Higher film viscoelasticity modulus could be assigned for FS01/MPAM film systems than for FS01/HPAM ones. The film conductivity result showed that FS01/HPAM or FS01/MPAM liquid film systems could delay the liquid drainage speed under dynamic conditions compared with FS01 ones. Bulk foam test based on Waring Blender method indicated that FS01/HPAM foam was more stable than FS01/MPAM. Compared with static bulk foam test, the extensional viscoelasticity and conductivity method could reflect the dynamic behavior of liquid films. [ABSTRACT FROM AUTHOR]

Gas-wetness of cores plays an important role on imbibition. Gas-wetness of cores, treated by various concentration fluorocarbon polymer Zonyl8740 (aq), was measured by the captive bubble. Subsequently, co-current and counter-current spontaneous imbibition were conducted on the various gas-wet cores both in air/wate and air/oil systems. Experimental results showed that, with the increase of concentration of Zonyl8740 solutions, gas-wetting ability against liquid on the cores gets stronger, gas recovery decreases, and the trapped gas saturation increases. Meanwhile, on the cores treated by the same concentration Zonyl8740 solution, air/water systems have a stronger gas-wettability than that of air/oil systems. [ABSTRACT FROM PUBLISHER]

The surface properties and mixed micellization behavior of binary combinations of ionic liquid surfactant, namely, 1-tetradecyl-3-methylimidazolium bromide ([C14mim]Br) with common cationic surfactants viz. dodecyltrimethylammonium bromide (DTAB), tetradecyltrimethylammonium bromide (TTAB), cetyltrimethylammonium bromide (CTAB), and cetylpyridinium bromide (CPB) have been investigated by surface tension and conductivity measurements. The composition of mixed micelles and the interaction parameter were evaluated from the critical micelle concentrations of single and mixed systems using Rubingh's theory. Activity coefficients of mixed systems show the extent of ideality of individual surfactant. In all mixed systems examined, deviation from ideal behavior was seen. Γmax, Amin, πCMC, and the standard Gibbs free energies of adsorption, standard Gibbs free energies of micellizationhave been determined. Theandvalues are negative indicating the spontaneity of micelle formation. [ABSTRACT FROM PUBLISHER]

This work deals with the problem of settling under gravity for coal-oil mixtures when the concentration of particles is large. The repulsive force necessary to ensure stability of coal particle is vital. The net forces acting on the particle include gravity, buoyancy, viscous drag force, and electrostatic repulsive force. Accordingly, the equation at the terminal velocity at settling is obtained along with a critical surface potential to prevent settling under gravity. [ABSTRACT FROM AUTHOR]

The surface dilational viscoelasticity properties of alkyl secondary alcohol ethoxylates solutions, C15-s-EO7, C15-s-EO12, and C15-s-EO20, were investigated using the oscillating barrier method and interfacial tension relaxation method in Langmuir trough. The influences of oxyethylene numbers on dilational properties were expounded. The results show that the dilational modulus decreases with an increase in polyoxyethylene numbers at low concentration, which may be attributed to the fact that the surface concentration of C15-s-EOn with lower EO numbers is greater than that of C15-s-EOn with higher EO numbers. However, an increase in polyoxyethylene numbers cause an increase in dilational modulus at high concentration, which may be attributed to the slower relaxation processes caused by the 'flat configuration' of the longer polyoxyethylene chain at the surface. The results from the interfacial tension relaxation method are in good agreement with the experimental results from oscillating barrier method. [ABSTRACT FROM AUTHOR]

Taking the aggregate structures of polystyrene-b-poly (ethylene oxide)-b-polystyrene (PS-b-PEO-b-PS) block copolymer in tetrahydrofuran (THF) and N,N-Dimethylformamide (DMF) solvents as the starting point, further experiments were carried out to change the aggregate morphologies by adding PEO selective solvent, water, into the primarily solutions. Primarily, the microcrystal 'platelets' and 'spherical' aggregates were obtained in THF and DMF, respectively. After water being added into the aggregated system in THF, the macrophase separation occurred in the solution, and the further adding of water led to the formation of large compound micelles (LCMs). Nevertheless, the adding of water into spherical aggregates in DMF only leaded the decrease of aggregate size. [ABSTRACT FROM AUTHOR]

The aggregation behaviors and microenvironmental characteristics of five sodium tri-n-alkylbenzene sulfonates (STABS) micelles have been investigated by electron paramagnetic resonance (EPR) and steady-state fluorescence quenching (SSFQ) techniques. The results indicated that the micropolarity of STABS micelles was less sensitive to the increase of the alkyl chain length, and showed slight decrease with the increasing solution concentration. The microviscosity of STABS micelles increased with the increase of the long alkyl chain length, decreased with the increase of the short alkyl chain length, and exhibited little increase when increase the solution concentration. The salinity of added inorganic salt exhibited obvious effect on the decrease of micropolarity and increase of microviscosity of STABS. These results suggested that these different alkyl chains showed different effects on the micellization of STABS and the salinity's effect was even bigger. [ABSTRACT FROM AUTHOR]

Based on the extended Langmuir's method, accurate analytic expressions for the electrical properties of cylindrical colloidal particle in a solution of symmetric electrolyte are derived from the nonlinear cylindrical Poisson-Boltzmann equation. Comparison is made with previous literature results. The present formulae have good agreement with literature values and are quite simple for practical use. [ABSTRACT FROM AUTHOR]

Synergistic effect for lowering interfacial tension in alkyl benzene sulfonates mixtures-alkane systems was studied by spinning drop tensiometer. The results show that surfactant mixtures of similar structure tend to give the same γmin for the same nmin, while the alkane preference curve of the surfactant mixtures with different structures take on the shape of that of surfactant with higher interfacial activity. In the case of surfactant mixtures with different interfacial activities, the one with lower activity will modify the hydrophilic-lipophilic balance of surfactant with higher activity and result in synergism/antagonism. [ABSTRACT FROM AUTHOR]

In this article, foaming properties and dynamic interfacial properties of a series of sodium 2,5-dialkyl benzene sulfonates in aqueous solutions were carried out to elucidate the relationship between foaming properties and dynamic interfacial properties. The properties of foams generated from bubbling air through different surfactant solutions were measured using a modified Bikerman device. The dynamic surface tension and surface dilational elasticity were obtained from an image analysis technique based on the oscillating bubble method. The surfactants molecular adsorption at the air/water interface was introduced with Rosen empirical equation and the rate of adsorption was determined from measurements of the dynamic surface tension. The surfactant with the longest alkyl chain shows the lowest dynamic surface activity, which lead to the lowest foam volume. The short ortho straight alkyl chain has little effect on the arrangement of molecules at the interface and the foam stability changes a little with the changing of the ortho alkyl chain length. The foam stability is correlated with both the higher surface dilational elasticity and the larger surface monolayer strength. [ABSTRACT FROM AUTHOR]

The dilational viscoelastic properties of 4,5-diheptyl-2-propylbenzene sulfonate (377) in the presence or absence of electrolyte were investigated by means of two methods: the interfacial tension response to sinusoidal area variations and the relaxation of an applied stress. The higher dilational modulus of 377 than ordinary surfactant indicates that the strength against perturbation of interfacial layer of the former is greater. This may due to the two long and flexible branched alkyl chains, which are easily cross-linked and entangled. Moreover, the results reveal that the added electrolyte results in screening of electrostatic interactions between the ionized groups, which decreased the interfacial dilational modulus. [ABSTRACT FROM AUTHOR]

The influence of two surface-active components, oleic acid and octadecanol, on the interfacial dilational viscoelasticity of an oil-water interfacial layer containing asymmetrical anionic gemini surfactant C12COONa-p-C9SO3Na has been investigated. The results show that surface-active component concentration is an important factor in controlling the dilational properties of mixed-adsorption layer. A small quantity of surface-active component may enhance the dilational modulus by forming densely packed mixed-adsorption layer through hydrophobic interaction, while the superfluous addition of surface-active components could sharply decrease the dilational modulus mainly due to the weakening of the crosslink and entanglement among long alkyl chains in surfactant molecules. [ABSTRACT FROM AUTHOR]