非离子表面活性剂缔合结构的物理化学性能研究进展

从浊点,表面张力表面吸附、胶束形成热力上行为、与离子表面活性剂的复配,与聚合物的相互作用,微乳液的热力学性质,在非水体系中的物化性能等方面总结了近年来国内外应用现代实验技术对非离子表面活性剂缔合结构物理化学性能的研究现状况,得到了许多有益的规律和结论,并对各个研究领域进行了展望。这地丰富表面活性剂的基础理论和进一步开发利用非离子表面活性剂具有重要意义。     

Cloud Point Extraction (CPE) of Parabens using Nonionic Surfactant Phase Separation

A cloud point extraction (CPE) method was developed using silicone-ethylene oxide surfactant, DC193C, to study the equilibrium phase separation of parabens in environmental water samples. The volume of the surfactant rich phase (V_s), aqueous phase (V_w), preconcentration factor (C_F), distribution coefficient (K_d), and percentage of recovery (%R) were evaluated to obtain the optimum condition for phase separation of parabens. Satisfactory results were obtained whereby the preconcentration factor for methylparaben, ethylparaben, propylparaben, and benzylparaben were close to 65, 60, 80, and 45, respectively, at 0.5% weight of surfactant. The presence of DC193C gave a low phase volume ratio but insignificant result was observed with the increased of surfactant concentration. The parabens were well separated on a reverse-phase Chromolith C₁₈ column (100 mm × 4.6 mm) with a gradient elution (acetonitrile: water; 30:70 v/v) and detected at 254 nm. The proposed method was successfully applied to environmental samples such as river water, treated wastewater, sea water, and tap water with satisfactory results. The method detection limit was 0.1–0.2 ppb and the recoveries were 71.2–97.7% with the relative standard deviations of 0.3–2.1%.     

非离子表面活性剂在油溶液中的流变性质

反胶团是形成Ｗ／Ｏ乳液或微乳液的基础。通过对若干表面活性剂和油二元系溶液粘滞系数的实际测量,发现不同的表面活性剂与油的组合,其粘滞系数性质有不同的表现。从这个结果可以确定反胶团粒子出现与否,而反胶团粒子的出现能够提供了一个简单的方法,来判断某未知油能否被乳化成Ｗ／Ｏ型乳液或微乳液。     

含非离子表面活性剂吐温-80的微乳液结构研究

采用非离子表面活性剂吐温-80,以石油醚为油相,正丁醇为助表面活性剂来制备微乳液。用稀释法测定并计算了Tween-80/石油醚/正丁醇/水体系O/W型微乳的结构参数。测量微乳液体系在15~30℃温度范围内的pH及电导,考察温度对微乳液体系的影响。向微乳液体系中加入PVP,测量体系的电导和接触角,考察水溶性高分子对微乳液体系的影响。结果表明微乳液体系的电导随温度的上升而变大,相同温度时,加入PVP会使体系的电导变大,接触角变小。     

十二烷基硫酸钠对非离子表面活性剂CM101浊点的影响

研究了阴离子表面活性剂十二烷基硫酸钠(SDS)对非离子表面活性剂CM101浊点的影响。结果表明:当SDS加入量为2%时,CM101的浊点提高到59.6℃,达到农药制剂热稳定性的要求。同时,该混合体系满足非理想二元表面活性剂复配增效的条件,表面张力和临界胶束浓度都有明显降低。     

非离子表面活性剂为溶媒的浊点萃取技术

非离子表面活性剂溶液在温度高于其浊点或有一定添加物存在时,会自动形成表面活性剂浓度很小的稀相和表面活性剂浓度很高的凝聚层相,存在于这一系统的溶质将不均匀地分配于二相。文章结合研究成果,综述了这一新型浊点萃取技术的基本理论和应用,同时也介绍了浊点萃取在微生物转化中的新应用。     

双生表面活性剂微乳液的制备及其相行为研究

制备了双生表面活性剂α-磺基硬脂酸聚乙二醇双酯钠盐/醇/正辛烷/水微乳液体系,绘制了其拟三元相图,探讨了不同碳链长度的醇及0.1mol/LKCl、NaOH、HCl溶液对微乳区域的影响,利用电导率分析了微乳液的结构类型。结果表明:以α-磺基硬脂酸聚乙二醇双酯钠盐作为乳化剂,可以制备稳定的微乳液。在中等链长范围内,作为助表面活性剂的醇类,链长的比链短的醇具有更好的助活作用。电解质溶液一般使微乳区域缩小,以电解质溶液或纯水为分散介质的微乳液的电导率变化趋势基本相同。     

Cloud Point Extraction of Four Triphenylmethane Dyes by Triton X-114 as Nonionic Surfactant

A method for removing four triphenylmethane dyes from wastewater by cloud point extraction with the nonionic surfactant Triton X-114 (TX-114) was developed. The triphenylmethane dyes were crystal violet, ethyl violet, malachite green and brilliant green. The cloud point of TX-114 generally increased in the presence of any of the four dyes. In the cloud point system, these dyes were solubilized into a coacervate phase that left a color-free dilute phase. The extraction efficiency of the dyes increased with the temperature, TX-114 concentration, and salt (NaCl and CaCl₂) concentration. More than 97% TX-114 in the dilute phase was recovered by adjusting the volume ratio of dichloromethane to the dilute phase. The Langmuir-type adsorption isotherm was used to describe the dye solubilization. The Langmuir constants m and n were calculated as functions of temperature. The results showed that the solubilization of the triphenylmethane dyes in the cloud point system was related to the partition coefficient and their molecular structures.     

Effect of Ethylene Oxide Group in the Anionic–Nonionic Mixed Surfactant System on Microemulsion Phase Behavior

The phase behavior of microemulsions stabilized by a binary anionic–nonionic surfactant mixture of sodium dihexyl sulfosuccinate (SDHS) and C12-14 alcohol ethoxylate (C_{12 − 14}E_j) that contains an ethylene oxide (E_j) group number, j, of either 1, 5, or 9 was investigated for oil remediation. The oil–water interfacial tension (IFT) and optimal salinity of the microemulsion systems with different equivalent alkane carbon numbers (EACN) were examined. The anionic–nonionic surfactant ratio was found to play a pivotal role in the phase transition, IFT, and optimal salinity. The minimum IFT of mixed SDHS − C_{12 − 14}E_j systems were about three times lower than those of neat SDHS systems. A hydrophilic–lipophilic deviation (HLD) empirical model for the mixed anionic–nonionic surfactant system with the characteristic parameter was proposed, as represented in the excess free energy term . The results suggested that the mixed system of SDHS − C_{12 − 14}E₁ was more lipophilic, while SDHS − C_{12 − 14}E₉ was more hydrophilic than the ideal mixture (no excess free energy during the microemulsion formation), and the SDHS − C_{12 − 14}E₅ system was close to the ideal mixture. The findings from this work provide an understanding of how to formulate mixed anionic–nonionic microemulsion systems using the HLD model for oils that possess a wide range of EACN.     

Gemini表面活性剂微乳液相行为的影响因素研究

研究了Gemini表面活性剂微乳液的界面相行为,考察了中间联接基团长度、表面活性剂和助表面活性剂的配比、醇链长和烷烃链长对相图的影响。结果表明：短链联接基团较易形成单相微乳液,表面活性剂用量较少且有较高的含水量;随着烷烃链长增加,形成O/W区域所需表面活性剂含量增加,且区域面积在逐渐减小;醇链长改变时,沿着油-（S＋A）轴都能形成W/O型微乳液。     

无机盐对非离子表面活性剂从水相到油相传质的影响研究

采用同位素示踪原子法研究了非离子表面活性剂在无机盐存在下从水相到油相传质的规律,发现无机盐能强烈地影响非离子表面活剂Ａｐ型和Ｓｐ型的传质行为,而且因无机盐性质的不同,表面活性剂结构的差异,传质行为亦会有很大的不同。     

Nonionic surfactants induced cloud point extraction of Polyhydroxyalkanoate from Cupriavidus necator

Polyhydroxyalkanoate synthesized by Cupriavidus necator DSM 428 was purified from the crude fermentation broth as such by performing nonionic surfactants (Triton X100, Triton X114 & Tergitol 6) induced cloud point extraction. Polyhydroxyalkanoate was extracted into the micelle-rich bottom phase (coacervate phase), while most of the cellular impurities partitioned into the aqueous phase. Cloud point temperatures and the extraction efficiency of different cloud point systems were studied at different pH value and in the presence of additives. Maximum extraction of biopolymer was achieved (recovery of 84.4%) with a purity of 92.49% at 3 pH with the addition of 0.1 M ammonium chloride in the mixed surfactant system at a reduced cloud point temperature of 33°C.     

Application of Counter-Current Solvent Extraction to the Separation of Naphthalene and Nonionic Surfactants

This study conducted counter-current solvent extraction to investigate the influence of solvent/solution volumetric ratio, solvent flow rate, and surfactant concentration on extraction efficiency. Fitting formulas for predicting the partition coefficients of the contaminant and surfactant between the aqueous and solvent phases were developed to optimize the counter-current solvent extraction. It is found that the solvent/solution volumetric ratio and the surfactant concentration had greater impact than the solvent flow rate on the extraction efficiency. The relationship between the partition coefficient K and the solvent/solution volumetric ratio or surfactant concentration was closely related to power function. Besides, the accuracy of the fitting formulas was consistent with the experimental results.     

相分离辅助方法对有机硅表面活性剂浊点萃取PAHs的影响

相分离性能和萃取率是评价浊点萃取(CPE)性能的两个重要因素.对于采用非离子表面活性剂的CPE,当溶液加热至浊点以上,仅依靠热运动来促使其发生相分离是十分缓慢的,因此通常需要一定的辅助方法来加速其相分离的进程.今利用两种聚醚型有机硅表面活性剂DC-193和DC-190,对蒽、菲、芘和苊四种多环芳烃(PAHs)进行浊点萃取研究,分别使用加热、加盐、离心和搅拌等辅助方法改变相分离过程的速度.通过测定表面活性剂富集相的体积百分率Vs/(Vs Vw)随时间的变化和最终的萃取率,研究上述四种不同辅助方法对相分离行为和萃取性能的影响.结果表明,相分离速度:加盐＜加热＜离心＜搅拌;Vs/(Vs Vw):搅拌＜离心＜加盐＜加热;萃取率:加热＜加盐≈离心＜搅拌.可见,离心与搅拌辅助CPE具有较大的优势,可同时提供更高的相分离性能和萃取率.与离心相比,搅拌的引入所需设备更简单,而且对于容器的体积没有限制,易于实现连续操作,更有望应用于实际的大规模水处理之中.     

双水相微胶束萃取对苯二酚研究

采用非离子型表面活性剂辛基酚聚氧乙烯醚(Triton X-114)组成的双水相系统(ATPS)萃取对苯二酚,依据胶束分相和分配,实现对苯二酚的萃取和分离。讨论表面活性剂浓度对萃取率的影响,尝试用反萃取方法回收进入微胶束相的对苯二酚。结果表明:双水相微胶束对对苯二酚的萃取率取决于Triton X-114的浓度,双水相微胶束对对苯二酚的萃取率随Triton X-114浓度的增加而增大;反萃取时溶液的pH值等因素对反萃取率的影响很大,通过调节pH值可以使反萃取率增大。     

Synthesis of Alkanolamide: a Nonionic Surfactant from the Oil of Gliricidia sepium

Oil of Gliricidia sepium with high contents of C18:2 (32.2 ± 0.3%) and C18:1 (23.8 ± 0.5%) fatty acids was used in the preparation of diethanolamide and epoxidised diethanolamide via transamidation. The epoxidised diethanolamide was synthesized by peroxyformic acid generated in situ by reacting formic acid and hydrogen peroxide with the oil of G. sepium, a renewable resource. The formation of the amide was monitored and confirmed using Fourier Transform Infrared Spectroscopy and Nuclear Magnetic Resonance. The epoxidised diethanolamide showed better surface-active properties than the diethanolamide in terms of emulsion stability, wetting property and foaming power.     

Cloud Point Extraction of Parabens Using Non-Ionic Surfactant with Cylodextrin Functionalized Ionic Liquid as a Modifier

A cloud point extraction (CPE) process using non-ionic surfactant (DC193C) to extract selected paraben compounds from water samples was investigated using reversed phase high performance liquid chromatography (RP-HPLC). The CPE process with the presence of β-cyclodextrin (βCD) functionalized ionic liquid as a modifier (CPE-DC193C-βCD-IL) is a new extraction technique that has been applied on the optimization of parameters, i.e., pH, βCD-IL concentration and phase volume ratio. This CPE-DC193C-βCD-IL method is facilitated at 30 °C, showing great losses of water content in the surfactant-rich phase, resulting in a high pre-concentration factor and high distribution coefficient. The developed method CPE-DC193C-βCD-IL did show enhanced properties compared to the CPE method without the modifier (CPE-DC193C). The developed method of CPE-DC193C-βCD-IL gives an excellent performance on the detection of parabens from water samples with the limit of detection falling in the range of 0.013–0.038 μg mL⁻¹. Finally, the inclusion complex formation, hydrogen bonding, and π–π interaction between the βCD-IL, benzyl paraben (ArP), and DC 193C were proven using ¹H NMR and 2D NOESY spectroscopy.     

Removal of Tannic Acid From Aqueous Solution by Cloud Point Extraction and Investigation of Surfactant Regeneration by Microemulsion Extraction

The aim of this work is the extraction of tannic acid (TA) with two commercial nonionic surfactants, separately: Lutensol ON 30 and Triton X‐114 (TX‐114).The experimental cloud point extraction results are expressed by four responses to surfactant concentration and temperature variations: extent of TA extraction (E), remaining solute (X_s,w) and surfactant (X_t,w) concentrations in dilute phase and volume fraction of coacervate (Φ_c) at equilibrium. An empirical smoothing method was used and the results are represented on three dimensional plots. In optimal conditions, the extraction extent of TA reaches 95 and 87 % using TX‐114 and Lutensol ON 30, respectively. Sodium sulfate, cetyltrimethylammonium bromide (CTAB) addition and pH effect are also studied. Finally, the possibility of recycling of the surfactant is proved.     

Cloud Point Extraction of Acetic Acid from Aqueous Solution

Abstract

A new acetic acid separation method was developed through a successful combination of cloud point extraction and complex extraction technology (CPE-SE), where an acetic acid complex compound formed and was solubilized in a surfactant micelle solution, instead of an organic solvent, and then concentrated into one phase by a phase separation process of the CPE technology. Since no organic solvent diluents were used, the new process was environmentally friendly and with a lower cost; meanwhile, the high selectivity of the complex extraction based on chemical complexation and high efficiency of CPE were also inherited as advantages over conventional solvent extraction process. In consideration of the compatibility and the related CPE characteristics, tributyl phosphate and PEG/PPG-18/18 Dimethicone were selected as complexing agent and surfactant of the CPE-SE system, respectively, and the extraction system was optimized by studying the effect of the main process parameters, including surfactant and complexing agent concentration, temperatures for the stirring and incubation steps, on the recovery and the distribution coefficient. A relative high recovery of 71.4% and a distribution coefficient of 1.4 were achieved simultaneously with the optimized process in the treatment of 0.1 M acetic acid solution. Based on its competitive extractability, high efficiency, low-cost, and environment friendlyness, the CPE-SE process was expected to be a potential separation method for a dilute acetic acid solution.