EFFECTS OF NH_4Cl ON THE INTERACTION BETWEEN POLY(ETHYLENE OXIDE) AND IONIC SURFACTANTS IN AQUEOUS SOLUTIONS

The interaction of poly(ethylene oxide)(PEO)with the ionic surfactants,sodium dodecylsulfate(SDS)and cetyltrimethylammonium chloride(CTAC)respectively,in aqueous solutions containing a certain concentration of NH_4Cl, is studied by the viscosity measurement.It has been found that the ion-dipole interaction between PEO and ionic surfactants is changed considerably by the organic salt.For anionic suffactant of SDS,the addition of NH_4Cl into solution strengthens the interaction between PEO and the headgroup o...

Performance improvement of ionic surfactant flooding in carbonate rock samples by use of nanoparticles

Various surfactants have been used in upstream petroleum processes like chemical flooding. Ultimately, the performance of these surfactants depends on their ability to reduce the interfacial tension between oil and water. The surfactant concentration in the aqueous solution decreases owing to the loss of the surfactant on the rock surface in the injection process. The main objective of this paper is to inhibit the surfactant loss by means of adding nanoparticles. Sodium dodecyl sulfate and silica nanoparticles were used as ionic surfactant and nanoparticles in our experiments, respectively. AEROSIL~？ 816 and AEROSIL~？200 are hydrophobic and hydrophilic nanoparticles. To determine the adsorption loss of the surfactant onto rock samples, a conductivity approach was used. Real carbonate rock samples were used as the solid phase in adsorption experiments. It should be noted that the rock samples were water wet. This paper describes how equilibrium adsorption was investigated by examining adsorption behavior in a system of carbonate sample（solid phase） and surfactant solution（aqueous phase）. The initial surfactant and nanoparticle concentrations were 500–5000 and 500–2000 ppm, respectively. The rate of surfactant losses was extremely dependent on the concentration of the surfactant in the system, and the adsorption of the surfactant decreased with an increase in the nanoparticle concentration. Also, the hydrophilic nanoparticles are more effective than the hydrophobic nanoparticles.

Effects of Ionic Surfactants on Bacterial Luciferase and α-Amylase

In order to study the effects of ionic surfactants on bacterial luciferase,the cationic surfactant dodecyltrimethylammonium biomide (DTAB) and anionic surfactant sodium dodecylsulfate (SDS) were chosen.For comparison with bacterial luciferase,α-amylase was used since these two enzymes have similar electrostatic potential and charged active sites.After the enzymes were treated with the surfactants,the catalytic properties of bacterial luciferase andα-amylase were assayed,and fluorescence spectroscopy and circular dichroism (CD) were used to analyze the alteration of the protein structure.The results showed that when the DTAB concentration was low,the cationic surfactant DTAB enhanced the enzymatic activities of bacterial luciferase andα-amylase.On the other hand,the anionic surfactant SDS did not alter the enzymatic activity.The main interaction of cationic surfactant DTAB and the negatively charged surface of the proteins was the ionic interaction,which could alter the environment for the enzyme to work when the DTAB/enzyme molar ratio was low.However,at high cationic surfactant concentration,the ionic interaction and hydrophobic interaction might destroy the secondary and tertiary structures of the proteins,leading to the loss of enzymatic activities.

Pseudo Peak Phenomena in Micellar Electrokinetic Capillary Chromatography by Using Ionic Surfactant

The origin of pseudo peak was studied by means of micellar electrokinetic capillary chromatography with cetyltrimethylaminium bromide as the pseudo stationary phase. It has been pointed that two peaks may appear for one component under certain conditions. Experiments showed that the relative areas of the two peaks of analyte depended on the time and the temperature of reaction between analyte and surfactant, and the concentration of surfactant in the sample solution. It means that the interaction between the analyte and the surfactant is a slow process, and a stable substance can be produced from the interaction. It is the substance and the analyte that may lead to the formation of two peaks. The fast interaction mechanism between the solute and the micellar should be queried from the experiment result.

Liquid-liquid Extraction System Based on Non-ionic Surfactant-salt-H_2O and Mechanism of Drug Extraction

Extraction behavior of chlorpromazine hydrochloride (CPZ) and procaine hydro- chloride (PCN) in the system described in the title was studied. Research shows that the extraction efficiency of CPZ can amount to 96% by twice extraction, while that of PCN is 77%. This system produces the distribution coefficients (KD) of 12.3 and 2.6 respectively for CPZ and PCN. Extraction mechanism is deduced according to ultraviolet and molecular fluorescence spectra variation of the drugs in the system studied.

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.

A Simple and Rapid Method for the Detection of Non-Ionic Surfactants

A spectrophotometric approach for the detection of non-ionic surfactant (Triton X-100) has been proposed in this paper. This method does not involve extraction of the ion-associate with harmful solvents, but employs adhesion of the ion-association of potassium/non-ionic surfactants complex and tetraphenylporphyrin tetrasulfonic acid obtained by vigorous shaking. The adhered ion-associate was dissolved with water and its absorbance was measured. The sensitivity for Triton X-100 was determined to be 0.146 (expressed as absorbance of 1 mg/L solution). The adhesion tendency of ion-associate was found to be dependent on the water contact angle, which in turn was influenced by a high adhesion of the ion-associate and by low blank values. In this respect, a tetrafluo-roethylene vessel was found to be the most suitable for the detection of non-ionic surfactants. This spectrophotometrical method is simply and rapidly performed by a procedure based on mechanical shaking and can be employed to detect non-ionic surfactants containing more than 7 polyethylene oxide units.

CALORIMETRIC STUDIES ON THE STRUCTURE OF MICROEMULSION WITH NONIONIC SURFACTANT

Enthalpic studies on the state of water in hex-adecane/hexanol/ AEO8/water system have been conducted. The results show that water exists in three states such as bound water,trap water and free water. The enthalpic effect of condition that water to oil ratio is in the abnormal rheology region, the negative thixotropy of the system is directly proportional to the enthalpy.

Mesoporous Silica Materials Synthesized via Sol-Gel Methods Modified with Ionic Liquid and Surfactant Molecules

Mesoporous silica materials were synthesized via a sol-gel method employing a room temperature ionic liquid （1-butyl-3-methylimidazolium tetrafiuoroborate, [bmim][BF4]） as a new solvent medium and further modified with surfactant （hexadecyl-trimethyl-ammonium bromide, CTAB） as a pore templating material. The synthesized samples were characterized by the transmission electron microscopy, X-ray diffraction, and N2 adsorption-desorption techniques. The results indicated that the mesoporous silica synthesized by using [bmim][BF4] and CTAB as mixed templates showed better mesostructural order and smaller pore size, compared with mesoporous silica materials synthesized by using single [bmim][BF4] as template under the same conditions. This indicates that the presence of surfactant can affect the microstructures of silica prepared by＇the present synthesis method.

Separation of Biphenyl Nitrile Compounds by Microemulsion Electrokinetic Chromatography with Mixed Surfactants

A mixture of nine biphenyl nitrile compounds with high hydrophobicity and similar structures was successfully separated by microemulsion electrokinetic chromatography (MEEKC) within 30 min. The buffer system contained 100 mmol/L sodium dodecyl sulfate (SDS), 80 mmol/L sodium cholate (SC), 0.81% heptane, 7.5% n-butanol, 10% acetonitrile and 10 mmol/L borate. The addition of SC, organic modifiers, sample preparation and temperature all showed remarkable effect on the separation. Meanwhile, the MEEKC method was briefly compared with micellar electrokinetic chromatography (MEKC) method.

Molecular dynamics simulation study onπ-πstacking of Gemini surfactants in oil/water systems

Whereas theπ-πstacking interactions at oil/water interfaces can affect interfacial structures hence the interfacial properties,the underlying microscopic mechanism remains largely unknown.We reported an all-atom molecular dynamics(MD)simulation study to demonstrate how the Gemini surfactants with pyrenyl groups affect the interracial properties,structural conformations,and the motion of molecules in the water/n-octane/surfactant ternary systems.It is found that the pyrenyl groups tend to be vertical to the interface owing to theπ-πstacking interaction.Besides,a synergistic effect between theπ-πinteraction and steric hindrance is found,which jointly affects the coalescence of liquid droplets.Therefore,the existence of aromatic groups and a moderate number of surfactants helps to form microemulsion.This work provides a molecular understanding of Gemini surfactants with aromatic groups in microemulsion preparation and applications.

Surfactant-free oil/water and bicontinuous microemulsion composed of benzene,ethanol and water

Generally,a microemulsion consists of oil,water,surfactant and sometimes cosurfactant.Herein,we report a novel suffactant-free microemulsion（denoted as SFME） composed of benzene,water and ethanol without the amphiphilic molecular structure of traditional surfactant.The phase behavior of the ternary system was investigated,finding that there were a single-phase region and a two-phase region in ternary phase diagram.The electrical conductivity measurement was employed to investigate the microregion of the single-phase region,and a bicontinuous microregion and a benzene-in-water（O/W） microemulsion microregion were identified,which was confirmed by freeze-fracture transmission electron microscopy（FF-TEM） observations.The sizes of the microemulsion droplets are in the range of 20-50 nm.

Temperature Dependent Phase Behavior of Pseudo-Ternary Thiourea X-100 Surfactant +1-Hexanol/Oil/Water Systems

Temperature dependent phase behavior of Pseudo-ternary Thiourea X-100 + 1-hexanol (1:5 molar ratios)/oil/water systems is reported. The influence of nature of hydrocarbon oil and type of electrolytes (weak as well as strong) has been investigated on the temperature induced phase behavior of the ternary system. At surfactant concentration, Φs = 40%, a “nose shaped” microemulsion region is observed. Below one-phase microemulsion region, Lα phase appears. The presence of NaCl decreases the domain size of 1Φ micellar region whereas oxalic acid first decreases the domain below Φw 18 in the lower boundry of the phase diagram. The critical weight fraction of water, Φwcri decreases in presence of both electrolytes. However, Φwmax increases in presence of oxalic acid and remains constant in presence of NaCl as compared to salt free system. Furthermore, when cyclohexane was replaced by a longer straight chain hydrocarbon, dodecane, the domain of the one-phase microemulsion region is tremendously increased.

利用Triton X-100提升巴氏芽孢杆菌脲酶活性的效果

微生物诱导碳酸盐沉积(MICP)技术是近年来发展起来的一种新型绿色加固技术,如何提升MICP技术的加固效能一直是学者关注的热点,本工作重点结合巴氏芽孢杆菌产脲酶原理和非离子表面活性剂的特点,设计采用非离子表面活性剂Triton X-100提升MICP效能的试验研究。结果表明:(1)在单因素试验结果的基础上,通过响应面试验分析确定了活性剂的最优处理条件,即掺量1.37%、处理时间5.02 h、处理温度34.28℃、菌胶比1∶2.11;(2)采用最优条件处理的巴氏芽孢杆菌对钙质砂进行加固后,钙质砂固化体碳酸钙含量和无侧限抗压强度分别提升了25.48%和22.83%;(3)非离子表面活性剂Triton X-100增大了巴氏芽孢杆菌的细胞膜通透性,一方面使得更多的胞内脲酶释放到细胞外,同时更多的尿素分子进入到细胞内,促进了尿素水解,提升了碳酸钙的生成速率;另一方面使得以细菌为核点生成的碳酸钙胶凝体的结构更为致密,在这两方面作用下,MICP效能得到有效提升。相关思路和研究结果可为MICP加固效果的提升提供新的参考和思路。

微乳液的制备及煤泥浮选应用研究

采取Schulman法制备煤油微乳液,从不同表面活性剂、亲水亲油平衡值(HLB值)、助表面活性剂中筛选最佳组分以确定煤油微乳液的体系组成。利用煤油/Tween 80-Span 80/正丁醇/水微乳液作为浮选捕收剂,对陕西南梁煤矿煤泥进行了系列浮选实验对比研究,结果表明,Span 80-Tween 80为复合乳化剂,正丁醇为助乳化剂,油水比为4∶1,HLB为9时,所制备的微乳液性能最稳定;制备微乳液为油包水型(W/O),整体粒径大小分布在10~100 nm,并且低含量状态下可以降低水的表面张力,从而实现良好的浮选效果。与煤油相比,在精煤灰分基本保持不变的情况下,精煤产率提高至65.12%,可燃体回收率达到94.78%,浮选完善指标达到72.45%,为选煤厂提高精煤产率,降低药剂消耗提供了思路。

食品中自微乳体系的组成、制备及促进生物活性物质生物利用的研究进展

随着人们健康膳食意识的增强,开发食品功能作用引起了人们的广泛关注。自微乳体系是一种由油相、表面活性剂、助表面活性剂和生物活性物质以一定比例混合后形成的无水预浓缩体系。通过自微乳体系荷载食品生物活性物质可改善其生物利用度,并充分发挥其生理及药理活性。本文系统综述了自微乳的基本性质、组分及制备方法,整理了近年来自微乳体系在食品领域促进生物活性物质生物利用的应用实例,为自微乳体系在食品领域的推广应用提供了参考。

以Cu(Ac)_(2)-Zn(Ac)_(2)溶液为水相的W/O微液滴尺度的有效调控

微乳液常被用来制备纳米材料,而对微液滴尺寸的有效调控对于纳米材料制备至关重要。本文研究了在Triton X-100微乳液体系中,以Cu(Ac)_(2)-Zn(Ac)_(2)电解质水溶液为水相时,微液滴尺度的变化情况。实验结果表明:在4~12nm的范围内,可以通过改变微乳液中水含量和电解质溶液种类来调节液滴的大小。在一定范围内,无论是水体系还是电解质溶液体系中,微液滴的平均粒径都随着水含量的增加而增大。电解质溶液中金属离子与水分子之间的作用力不同,导致微液滴的粒径分布呈现出不同的变化。需要注意的是,电解质的加入对于微乳液的外观和稳定性没有影响。在以链状烷烃作为油相形成的Cu(Ac)_(2)-Zn(Ac)_(2)电解质微乳液体系中,微液滴的粒径分布更加均匀。最后,本文采用所述的微乳液方法成功制备了CuO-ZnO纳米颗粒。本研究结果对于实现微乳液液滴尺度的可控调节和纳米材料的制备具有重要意义。

Ag/ZIF-8复合材料的制备及其光降解性能

在无表面活性剂微乳液中制备了ZIF-8材料,并采用光致还原法将纳米Ag负载于ZIF-8表面,制备了负载量不同的系列Ag/ZIF-8复合材料。XRD、SEM、XPS、UV-DRS以及光电性能测试表明Ag成功负载到ZIF-8中,且光电性能大幅度提高。对比考察了ZIF-8和Ag/ZIF-8对有机染料的光降解效率,提出了光催化机理。由于Ag纳米粒子和ZIF-8的协同效应,其所形成的异质结构Ag/ZIF-8表现出了优异的光催化活性。

无表面活性剂微乳液体系双甲基增强硅气凝胶的制备与性能研究

硅气凝胶是由SiO_(2)粒子相互聚合组成的一种新型多孔功能材料,以水/乙醇/正己烷无表面活性剂微乳液体系为溶剂,采用酸碱两步溶胶-凝胶法在无需溶剂替换和表面改性的前提下制备无表面活性剂微乳液体系双甲基增强硅气凝胶。采用SEM、FT-IR、BET和接触角等手段对所得样品进行表征,确定增强相二甲基二乙氧基硅烷的最适添加量。结果表明:当二甲基二乙氧基硅烷添加量为0.08 mol时,无表面活性剂微乳液体系双甲基增强硅气凝胶的密度为0.157 g/cm^(3),孔隙率为93%,BJH平均孔径3.92 nm,疏水角为152.5°。

SDS与AEO_(3)复配对褐煤润湿性的影响分子动力学模拟研究

为了探究阴离子与非离子表面活性剂复配对低阶煤润湿性影响的微观机理,采用分子动力学模拟的方法(MD),研究了阴离子表面活性剂(SDS)与非离子表面活性剂(AEO_(3))及二者复配体系对褐煤润湿性的影响。研究结果表明:当SDS与AEO_(3)复配时,煤/水吸附层厚度最大,为36.35×10^(-10) m,将褐煤分子层的58.83%润湿,此时水分子的扩散系数显著增加,从而提高了煤与水分子碰撞的概率,进而增强了水对褐煤的润湿性;在SDS/AEO_(3)复配体系中,褐煤与水、表面活性剂与水间的相互作用能均大于SDS与AEO_(3)单独作用体系;煤与水、表面活性剂与水之间的相互作用能均由非键能提供,非键能中静电力能占比在82.28%以上,而范德华力能贡献占比则极小,甚至会抑制表面活性剂与水间的相互作用;SDS、AEO_(3)及SDS/AEO_(3)复合情况下与水之间所产生的氢键键长差别不大,但是SDS/AEO_(3)复合情况下与水产生的氢键数量要多于SDS、AEO_(3)单独与水产生的。