Synergistic anionic/zwitterionic mixed surfactant system with high emulsification efficiency for enhanced oil recovery in low permeability reservoirs

Emulsification is one of the important mechanisms of surfactant flooding. To improve oil recovery for low permeability reservoirs, a highly efficient emulsification oil flooding system consisting of anionic surfactant sodium alkyl glucosyl hydroxypropyl sulfonate(APGSHS) and zwitterionic surfactant octadecyl betaine(BS-18) is proposed. The performance of APGSHS/BS-18 mixed surfactant system was evaluated in terms of interfacial tension, emulsification capability, emulsion size and distribution, wettability alteration, temperature-resistance and salt-resistance. The emulsification speed was used to evaluate the emulsification ability of surfactant systems, and the results show that mixed surfactant systems can completely emulsify the crude oil into emulsions droplets even under low energy conditions. Meanwhile,the system exhibits good temperature and salt resistance. Finally, the best oil recovery of 25.45% is achieved for low permeability core by the mixed surfactant system with a total concentration of 0.3 wt%while the molar ratio of APGSHS:BS-18 is 4:6. The current study indicates that the anionic/zwitterionic mixed surfactant system can improve the oil flooding efficiency and is potential candidate for application in low permeability reservoirs.

Phase Separation and Microstructure of Mixed Surfactants Solution Containing Cationic Geminis and Traditional Anionic Surfactant

The properties of aqueous two-phase system (ATPS) of mixed solution containing gemini cationic surfactant trimethylene-1,3-bis(dodecyldimethyl ammonium) bromide (12-3-12, 2Br-) and traditional anionic surfactant sodium dodecyl sulfate (SDS) with or without added salt have been studied. An ATPS is formed in a narrow region of the ternary phase diagram different from that of traditional aqueous cationic-anionic surfactant systems. In ATPS region, the lowest total concentration of surfactants varies with the mixing ratio of geminis to SDS. Photographs obtained from freeze-etching, negative-staining and transmission electron microscopy show that the microstructures of two phases are different from each other. Micelles and vesicles can coexist in a single phase. The addition of salts can change the phase diagram of ATPS. Furthermore, the added salts promote the aggregation of rod-like micelles to form coarse network structure that increase the viscosity of solutions. The negative ions of the added salts are the determining factor.

Theoretical and Experimental Studies on Interactions of Cationic-Anionic Surfactants

Typical cationic and anionic surfactants were chosen and their interactions were calculated by quantum chemical method. Interaction energies are -0.2378 kJ·mol-1, -3.3394kJ·mol-1 and 0.1204kJ·mol-1 for the molecular pairs with fluocarbon and hydrocarbon chain: C4H10/C5H12, C4F10/C5H12, and C4F10 /C5F12, respectively. When hydrophilic group with cationic and anionicions is introduced, interaction energies are -287.40kJ·mol-1, -311.18kJ·mol-1 and -345.83kJ·mol-1. The results show that there is strong static interaction between cationic and anionic surfactants. It has been predicted that mixed monolayer may be formed and surface activity is enhanced favorably, especially for mixtures of cationic and anionic surfactants with fluocarbon and hydrocarbon chains. The anionic surfactants, sodium octadecylbenzenesulfonate perfluopolyetherbenzenesulonate(ANF-I) was synthesized, mixture effects of ANF-I with sodium octadecylbenzenesulfonate or dodecyldimethyl benzylammonium bromide were studied. The results indicate that the efficiency of mixing increased and the theoretical prediction was testified. These results can provide useful information for the design of new surfactants.

Surface Activity Interactions in Aqueous Solution of Anionic Surfactants with a Water Treatment Protein from <i>Moringa oleifera</i>Seeds

The interaction of anionic surfactants sodium dodecylbenzenesulphonate (SDBS) and sodium bis (2-ethyl-1-hexylsulfosuccinate) (AOT) with the water treatment protein extracted from Moringa oleifera seeds has been investigated by surface tension measurements. The results were compared with previously reported studies using surface tension and zeta potential measurements of the same protein with an anionic surfactant sodium dodecylsulphate. There is a strong electrostatic interaction between the protein and the surfactants characterized by a local maximum at intermediate surfactant concentration. This surfactant concentration depends on the protein concentration and corresponds to the surfactant concentration at the point of charge reversal (zeta potential = 0 mV). The number of surfactant molecules required to neutralize the positive charges on the protein was found to be 8 per protein molecule.

Anionic Surfactants Levels in M’Koa Lake Water (Jacqueville, Cote d’Ivoire)

In this study, anionic surfactants concentrations and other physico-chemical parameters of surface water quality were assessed in the water of M’Koa Lake in the city of Jacqueville (C?te d’Ivoire). Three sampling campaigns were conducted at different seasons at six (6) sampling stations, identified in M’koa Lake by taking into account potential sources of pollution. The analyses of physico-chemical parameters were carried out using both the French AFNOR standard and the methods described by Rodier. The anionic surfactants concentrations were performed by using the methylene blue colorimetric method. The average concentrations of anionic surfactants in the water of M’koa Lake ranged from 0.23 ± 0.04 mg·L-1 to 1.43 ± 0.68 mg·L-1. They are high compared to both population density and socio-economic activities of Jacqueville’s town. These values can be explained by the characteristics of the studied Lake that do not allow enough dilution of the discharged effluent. The results indicate that M’koa Lake is subjected to harmful pollution by anionic surfactants. And among the physicochemical parameters studied, only turbidity and transparency values show water quality deterioration, favoured by wastewater discharge and direct human activities around the Lake.

Effect of an Anionic Surfactant on Hydraulic Conductivities of Sodium- and Calcium-Saturated Soils

The effect of sodium dodecylbenzenesulfonate (SDBS), an anionic surfactant used widely in household products and industrial processes, on saturated hydraulic conductivities (Ksat) of an Anthrosol saturated with sodium (Na-soil) or calcium (Ca-soil) was analyzed in a laboratory experiment using the constant head method, and adsorption and dispersion experiments were also conducted to infer the possible mechanisms of Ksat fluctuations. The results showed that SDBS was more intensely adsorbed in the Ca-soil than in the Na-soil. With an increase in the SDBS concentration, the stability of the Na-soil suspensions decreased when the SDBS concentration was less than 1.2 mmol L-1 and then above this concentration, increased markedly, while the stability of the Ca-soil suspensions increased gradually at all SDBS concentrations studied. With an increase in the SDBS concentration, the Ksat of the Na-soil increased, which resulted mainly from the increase of water channels in the soil because of the coagulation of the soil particles, while the Ksat of Ca-soil decreased mainly on account of the clogging of partial water channels by precipitated Ca(DBS)2 and the fine soil particles generated.

Synthesis and Characterization of Zirconia Nanocrystallites by Cationic Surfactant and Anionic Surfactant

Study on nanomaterials has attracted great interests in recent years. In this article, zirconia nanocrystallites of different structures have been successfully synthesized via hydrothermal methods with cationic surfactant （CTAB） and anionic surfactant （SDS）, respectively. Differential Scanning Calorimeter （DSC-TG）, X-ray Diffractometer （XRD）, Transmission Electron Microscope （TEM）, Ultraviolet-Visible （UV-vis） and N2 adsorption-desorption analyses are used for their structure characteristics. The results show that the cationic surfactant has a distinctive direction effect on the formation of zirconia nanocrystallites, while the anionic surfactant has a self-assembly synergistic effect on them. The sample synthesized with the cationic surfactant presents good dispersion with the main phase of tetragonal zirconia, and the average nanocrystal size is around 15 nm after calcination at 500 ℃. While the sample synthesized with the anionic surfactant exhibits a worm-like mesoporous structure with pure tetragonal phase after calcination at 500 ℃ and with good thermal stability.

Synthesis of Silica Hollow Spheres with Diameter Around 50 nm by Anionic Surfactant

Silica hollow spheres（SHSs） have attracted great attention because of their low toxicity, low density, large surface area, high chemical and thermal stability, and surface permeability. They can be widely applied in storage^[l], catalysis^[2], drug deli- very^[3,4], low-dielectric-constant materials^[5], low-refractive materials^[6-8], and so on. Up to now, there have been various methods to produce SHSs. Inorganic^[9] or organic particles^[10], such as polystyrene or calcium carbonate, were used as hard templates to create hollow cavities, However, the multistep synthetic process and the lack of structural robustness of the shells upon template removal process weaken their applica- tion. Soft templates, including oil-in-water emulsions^[11,12], vesicles^[13], micelle^[14,15] and gas bubbles^[16], are applied widely.

Improved Ti-containing Mesoporous Silica Catalyst Synthesized by Using Anionic Surfactant as Co-template

Ti-containing mesoporous silica materials(Ti-MSs) with isolated tetrahedrally coordinated Ti species have been widely applied in bulk molecular catalysis. Herein, Ti-MSs were synthesized using anionic surfactant SDS as the co-template. The SDS molecular assembled structures can interact with silica species through the interface hydrogen bonds leading to the formation of mesoporous silica structure with compact Ti-O bonds, lower hydrophilicity and low template cost. The influence of adding SDS as the co-template on the oxidation of styrene with aqueous H_2O_2 as the oxidant was investigated. Ti-MSs using SDS as the co-template showed better catalytic performance as compared with mesoporous titanium silicate synthesized with CTAB serving as the sole template. Moreover, the Ti-MSs synthesized at a Ti/Si ratio of 0.005 demonstrated an optimized performance for styrene oxidation with styrene conversion improved by 14.8%, benzaldehyde selectivity improved by 13.7% and styrene oxide selectivity improved by 9.2% when the reaction time was 6 h.

Synthesis and Surface Activity of Cashew-Based Anion-Nonionic Surfactants

Four novel anion-nonionic surfactants were synthesized using cashew phenol as raw material. The four structures were characterized by IR and elemental analysis. Their surface activities were investigated. Their critical micelle concentrations (CMC) are 9.30 × 10 –3 mol/L, 8.50 × 10–3 mol/L, 8.10 × 10–3 mol/L and 7.71 ×–3 mol/L respectively, and the corresponding surface tensions at CMC are 28.38 mN/m, 28.60 mN/m, 30.40 mN/m and 30.00 mN/m respectively. The contact angles of the solutions on sheet galsses were measured to observe their surface wettabilities. The effects of their concentrations, the concentrations of NaCl and temperature on their foaming capacity and foam stability were studied.

Development and Prospect of China’s Anionic Surfactant Industry

The development process of anionic surfactants in China was reviewed.The current status of anionic surfactants in China was analyzed.The overall situation of sulfonation equipment was introduced,and the development trend of anionic surfactant industry in China was prospected.

Overview of Simple Test for Determination of Surfactants by Adhesion Method

A simple, sensitive, and rapid analytical method is reported for the determination of surfactants. This is based on the use of an oppositely charged dye as the ion pair to form an ionic associate with the surfactant in a vessel, thus affording ion-associated adhesion on the inner wall of the vessel. After the adhesion, the remaining solution in the vessel is removed, and the ionic associate is dissolved in a suitable solvent. The absorbance of the resulting solution is measured spectrophotometrically to determine the concentration of the surfactant. Further, the mechanism of adhesion is elucidated.

STUDY ON NEUTRAL DEINKING OF ONP WITH NON-IONIC SURFACTANTS

The ONP neutral deinking performances of fatty alcohol polyoxyethylene ether with different EO value were investigated in this paper. Meanwhile, the synergistic effects of different non-ionic surfactants, the co-operation of non-ionic surfactants with anionic surfactants,and the effects of different salts added into the above two systems on deinkability were also studied. The results showed the deinking performance of A7 was good. But the synergistic effect of A7 and A4 was better. In addition, the accession of salt W2 could improve the deinking efficiency, and the brightness of the deinked pulp was 1.0%ISO higher than that of A7 and A4.

Study on aqueous two-phase systems of the mixture SDS/CTAB surfactants

The phenomenon of two dilute aqueous phases composed of sodium dodecylsulfate(SDS) and cetyl trimethyl ammonium bromide(CTAB) was investigated under various conditions such as concentrations and molar ratios of the two surfactants, the addition of sodium chloride and temperature. Vesicles formation was found in the both phases by TEM image.

Iron Bearing Minerals Flotation from Silica Sand Using Hydroxyl Surfactants

A technological clayey sandstone sample from Wadi Qena locality, Eastern Desert of Egypt, was directed to processing. Fine kaolin and clean silica sand were produced after intensive attrition scrubbing of the sample. To increase the quality of the produced silica, it was subjected to reverse anionic flotation to minimize its iron content. In this respect, conventional flotation tests using three anionic oxyhydryl surfactants namely: sodium dodecyl benzene sulphonate, sodium naphtha sulphonate, and sodium dodecyl sulphate, were tried. Results showed a privilege action for sodium dodecyl sulphate to remove most of the iron oxide content of the sample. A statistical Box-Behnken design was constructed to optimize the process efficiency. It was shown that from a flotation feed contained 360 ppm Fe2O3 and 1190 ppm Al2O3, sand concentrate contained 29 ppm Fe2O3 and 564 ppm Al2O3, was produced. The optimum flotation conditions were 3.86 kg/t sodium dodecyl sulphate dose, 3.22 flotation pulp pH, 1226 rpm impeller speed, and 22.24 L/min airflow rate. Variables interaction effects results showed that flotation separation efficiency was significantly influenced by air flow rate and cell impeller speed of the process.

Pilot test of polymer microsphere alternate surfactant flood(PMAS)with mixtures of anionic-cationic surfactants under harsh conditions in a sandstone reservoir

The first pilot test of polyacrylamide microsphere alternate surfactant flood(PMAS)with mixtures of anionic-cationic surfactants(Sa/c)was carried out for a high-temperature,high-salinity,and highhardness sandstone reservoir to demonstrate the potential of this novel technique to improve oil recovery.A critical micelle concentration(CMC)of 4.82 mg/L,an ultralow interfacial tension(IFT)of 8104 mN/m,and a high oil solubilization of 22 were obtained.Static and dynamic adsorptions of Sa/c on natural core containing 15 wt%clay were reduced to about 2.20 and 0.30 mg/g-core,respectively,with the addition of adsorption inhibitor(AI).Since June 2014,the pilot test of PMAS was carried out in a Sinopec reservoir with a temperature of 87C,a salinity of 260,393 mg/L,and a hardness of 6,401 mg/L.Twelve cycles of alternative injection of 0.0125 PV Sa/c with a concentration of 0.1%and 0.0125 PV polyacrylamide microsphere with a concentration of 0.2%were conducted at an injection rate of 0.1 PV/yr,for a total of 0.3 PV chemical injection.As a result,the net daily oil production increased from 0 t to 6.5 t,and the water cut decreased from 96.3%to 93.8%,leading to an ultimate improved oil recovery of 6.3%original oil-in-place.

亚甲蓝分光光度法测定水中阴离子表面活性剂含量的方法改进

对亚甲蓝分光光度法(GB 7494—1987)测定水中阴离子表面活性剂含量进行了方法改进。以毒性相对较小的二氯甲烷取代三氯甲烷作为萃取剂,试管取代分液漏斗,利用振荡器进行萃取。结果表明:改进方法的最佳萃取时间为1.5 min,单个样品的分析时间在10 min以内;十二烷基苯磺酸钠标准曲线的线性范围在2.0 mg·L^(-1)以内,检出限(3s/k)为0.0297 mg·L^(-1);对十二烷基苯磺酸钠标准溶液重复测定6次,测定值的相对标准偏差(n=6)均小于9.0%;对空白样品进行加标回收试验,回收率为95.0%~99.1%。

驱油用阴离子表面活性剂的识别与检测方法研究

针对油井采出液中复杂离子条件下驱油用阴离子表活剂难以检测的问题,利用高效液相色谱系统,建立了油田产出液中驱油用阴离子表面活性剂的识别与检测方法,并验证了方法的准确性与有效性。该方法具有快速准确、操作简便、适用性强的特点。确定了表面活性剂从油田产出液(包括原油和污水)中分离的方法,矿场应用效果较好,为油田驱油用阴离子表面活性剂的矿场测试提供技术支持。

阴阳离子表面活性剂对煤层自转向酸液的性能影响及优选

针对煤矿粉尘污染严重问题,研究了煤层OAPB自转向酸液均匀布酸,从而提高煤体含水率,借助黏度、荷电性、官能团等方法研究了不同阴阳离子表面活性剂对自转向酸液增黏、润湿性能的影响规律,探究了性能变化的内部原因,并根据测试结果进行了优选。结果表明:阳离子表面活性剂会直接导致自转向酸液破胶,阴离子表面活性剂的添加使自转向酸液黏度增加;SSA/SDBS润湿性能较好,表面张力最低为24.12 mN/m;SSA/SDBS-16表面张力值总体较高,自身润湿性能差,对煤体的吸附性能也较弱;通过红外实验发现在SSA/SDBS作用下OAPB分子更倾向于形成氢键,并通过三轴渗流实验验证了自转向酸液的渗流效果。

异构癸醇聚氧乙烯醚硫酸钠与椰油酰胺丙基羟磺基甜菜碱的协同作用

将EO数为5的异构癸醇聚氧乙烯醚硫酸钠(1005S)与椰油酰胺丙基羟磺基甜菜碱(CHSB)以不同比例混合,对混合体系的性能进行研究,主要包括平衡表面张力、动态表面张力、乳化性能、泡沫性能和润湿性能。结果表明:对于复配体系,当CHSB与1005S以质量比5∶5进行复配时,临界胶束浓度(cmc)为9.8×10^(-3) g/L,临界胶束浓度下的表面张力(γ_(cmc))为31.7 mN/m,混合体系在乳化、润湿、泡沫性能上均优于单一组分,具有很好的协同增效作用。阴/两性离子表面活性剂复配效果优异,为环保高效的生产目标提供了科学依据。