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。     

D5反胶束体系的制备及其增溶特性的研究

以对生态环境友好的D5(十甲基环五硅氧烷)替代传统反胶束体系中的烷烃作为连续相介质,制备新型的D5反胶束体系,并对该体系的增溶行为进行研究,分别比较了阴离子表面活性剂、阳离子表面活性剂、非离子表面活性剂的D5反胶束体系的增溶水量。结果表明,用非极性的D5替代传统反胶束体系中的烷烃来制备对生态环境友好的反胶束体系的方法可行;在某些需要助表面活性剂才能形成的D5反胶束体系里,助表面活性剂醇的用量和表面活性剂的类型及其浓度都影响着体系的增溶水量;非离子表面活性剂形成的TX-10/正辛醇/D5反胶束体系增溶水量最大。     

阴离子表面活性剂与阳离子表面活性剂的相互作用(Ⅱ)——稀溶液性质

介绍了阴离子表面活性剂与阳离子表面活性剂相互作用的稀溶液性质。在水溶液中,阴/阳离子表面活性剂混合体系因分子间极性基正/负离子的强静电吸引作用,易形成棒状胶束,浓度超过cmc后,可能发生聚集,出现浑浊、分相等情况,使用短链表面活性剂、引入聚氧乙烯链及非等摩尔复配在一定程度上可避免这种现象。均相阴/阳离子表面活性剂混合溶液,对非极性有机物的增溶存在增效作用,但对极性有机物的增溶能力则有可能下降;在一定浓度及混合比范围内还可能出现类似非离子表面活性剂的浊点效应。     

阳离子,非离子混合表面活性剂体系在油水两相间传质过程中的？…

本文测定了阳离子表面活性剂和非离子表面活性剂在水－正庚烷中的分配系数，以及混合阳离子，非离子表活剂在水－庚烷中的分配系数。通过分配系数和有关假定，计算出两种表面活性剂在单独和混合分配时的ΔＧＷ→０，ΔＳＷ→０，ΔＨＷ→０值。并利用热力学函数推算出阳离子和非离子表活剂在小于临界胶束浓度时的分配过程中的分子间相互作用系数β值。     

Triton X-100-无机盐双水相体系的相平衡模型及碱性蛋白酶在该体系中的分配系数模型

研究了Triton X-100-无机盐双水相萃取体系在298 K时的相行为,建立了包含界面吸附效应的非离子表面活性剂双水相液-液平衡模型及碱性蛋白酶在其中的分配系数模型,验证了模型的可靠性和适用性.研究发现,该模型对中性范围的非离子表面活性剂双水相萃取体系的相行为及碱性蛋白酶分配平衡的模拟效果较好;非离子表面活性剂在水溶液中由于易结合离子而影响相行为,使体系更易分相;无机盐增大了碱性蛋白酶的表面疏水性,使碱性蛋白酶在疏水相中增溶.     

阳离子、非离子混合表面活性剂体系在油水两相间传质过程中的相互作用

本文测定了阳离子表面活性剂（CTAB）和非离子表面活性剂（TritonX－100）在水－正庚烷中的分配系数（Co＜cmc），以及混合阳离子、非离子表活剂在水－庚烷中的分配系数（Co＜cmc）。通过分配系数和有关假定，计算出两种表面活性剂在单独和混合分配时的△GW→0、△SW→0、△HW→0值，并利用热力学函数推算出阳离子和非离子表活剂在小于临界胶束浓度时的分配过程中的分子间相互作用系数β值。     

聚醚型非离子表面活性剂的浊点及其影响因素

总结了非离子表面活性剂浓度、外加聚合物、离子表面活性剂、无机电解质、助表面活性剂等对聚醚型非离子表面活性剂水溶液浊点的影响规律 ,发现聚合物由于其结构和分子量不同对浊点的影响也不同 ,一般可使浊点降低 ;加入离子表面活性剂可以和非离子表面活性剂形成混合胶束 ,从而使浊点升高 ;无机盐由于存在盐析和盐溶两种不同效应而对浊点的影响比较复杂 ;醇和有机酸等助表面活性剂根据其碳链的长短不同而影响浊点。这些规律对非离子表面活性剂的研究和应用有一定的指导意义。     

生物表面活性剂对疏水性有机物的增溶特性

在提高疏水性有机污染物的生物可利用性方面,生物表面活性剂的增溶效果是关键.通过实验测试了单一鼠李糖脂生物表面活性剂、复配表面活性剂(鼠李糖脂-非离子表面活性剂)对疏水性有机污染物增溶性能的影响,在此基础上,进一步考察了无机盐对复配表面活性剂增溶效果的影响.结果表明:鼠李糖脂质量浓度在临界胶束质量浓度之上时,长链烷烃和多...     

添加剂的浓度对非离子表面活性剂AEO9浊点的影响

各类添加剂都能对非离子表面活性剂的浊点产生影响.今研究了离子型表面活性剂、增溶物和电解质类添加剂在不同浓度下对非离子表面活性剂AEO9浊点的影响.其中离子型表面活性剂和增溶物类添加剂可在极低的浓度上改变AEO9的浊点,且随着添加剂加入浓度的增加,AEO9的浊点也逐渐增加,当添加剂浓度达到离子型表面活性剂或增溶物的临界胶束浓度时,AEO9的浊点将出现急剧上升.而电解质类添加剂对AEO9浊点的影响表现出具有临界浓度现象,只有当添加剂的浓度达到相应的临界浓度之后,具有盐析效应的电解质将使AEO9浊点线性下降,而具有盐溶效应的电解质则使AEO9浊点线性升高,且不同电解质相应的临界浓度随着其阴离子的感胶离子数的增大而线性增加,同时其对AEO9浊点的改变程度则随着阴离子的感胶离子数的增大而线性下降.     

铝、铍、铁、钪多元络合物显色反应中阳离子、非离子混合表面活性剂的作用

尽管各种表面活性剂在分光光度法中的应用日益广泛,但对混合表面活性剂的研究仍报导较少。Watanade曾研究了在阴离子和非离子型混合表面活性剂存在下,用1-(2-吡啶偶氮)-2-萘酚测定钴,郑用熙等用阴-阳混合型表面活性剂用铬天青S测定铝,戚文彬等研究了阴离子和非离子表面活性剂混合液在Ag~ -5-Cl-PADAB体系中的协同增色作用。作者曾在两性、非离子表面活性剂存在下比较满意地用铬天青S测定了不同材料中的Sc、U,并发现除两性表面活性剂外,阳离子与非离子表面活性剂亦可形成混合胶束,对体系有较好的增敏、增溶及增稳作用。目前阳离子表面活性剂应用广泛,如能深入研究这两种混合表面活性剂的作用及有关机理,并推广应用,将对胶束增溶分光光度法有所促进。本文是在Al、Be、Fe、Sc同铬天青S、阳     

双水相胶束萃取苯酚

根据胶束的加溶原理和非离子表面活性剂系统在浊点温度以上自动分相的现象 ,采用TritonX - 10 0胶束系统萃取苯酚 .结果表明 :苯酚的比胶束加溶量与其在水相的平衡浓度成比例关系 .测定了比例系数 ,即加溶平衡常数 .由此建立了数学模型 ,讨论了表面活性剂浓度、溶质浓度、pH值等因素对萃取率的影响 .模型计算结果和实验结果都说明 ,调节pH值可以反萃取苯酚的原因是苯酚电离改变了加溶平衡常数     

Study of nonionic surfactants on HVOCs removal from coacervate solutions using cocurrent vacuum stripping in a packed column

ABSTRACT

Cloud point extraction has been shown to be an effective technique to remove hydrophobic volatile organic compounds (HVOCs) from aqueous solution using nonionic surfactant. A cocurrent vacuum stripper is used to recover the surfactant in coacervate phase from extraction for economic viability. The solutions containing two series of aromatic and chlorinated HVOCs. Surfactants studied were alkyl phenol ethoxylates, secondary alcohol ethoxylates (AEs), and branched secondary AEs. From equilibrium measurements, the apparent Henry’s law constant (volatility) of the HVOCs in surfactant solution decreased with increasing HVOCs hydrophobicity due to solubilization of the HVOCs in micelles. The results showed that the mass transfer of HVOC decreases due to the solubilization enhancement of the HVOCs.     

Cloud Point Extraction of Glycyrrhizic Acid from Licorice Root

Abstract

An attempt has been made to extract glycyrrhizic acid (GA) from licorice root by surfactant mediated cloud point extraction (CPE) using non‐ionic surfactant (Triton X‐100). Almost all of the GA molecules were concentrated in the surfactant‐rich phase (also called coacervate phase) after phase separation. The pH is the most critical factor regulating the distribution of GA in the micelle which related to the ionization form. The other effects of the concentration of GA and the surfactant, the temperature, and the salt concentration on the extraction efficiency of GA in the coacervate phase and aqueous phase have been studied. The mechanism of CPE of GA was explored with transmitting electron microscopy. It was deduced that aggregate GA molecules were adsorbed on micelles' outer poler mantle and inner cross‐linked micelles at high GA concentrations in coacervate phase.     

Microemulsion Extraction of Monascus Pigments from Nonionic Surfactant using High Polarity of Diethyl Ether as Excess Oil Phase

Stripping of organic compound from nonionic surfactant micelle aqueous solution is indispensable for many industrial processes. In this paper, a relatively high polarity diethyl ether was screened for forming Winsor I microemulsion, which was used for stripping of organic compound from nonionic surfactant. Setting up extractive fermentation of Monascus pigments in Triton X-100 aqueous solution as a model, cloud point extraction of Monascus pigments from fermentation broth, and back-extraction of Monascus pigments from the coacervate phase of cloud point system by Winsor I microemulsion were conducted. Monascus pigments were successfully separated from nonionic surfactant into the excess diethyl ether phase.     

Mechanism of antifoam behavior of solutions of nonionic surfactants above the cloud point

Aqueous solutions of nonionic surfactants exhibit low foaming above their cloud point, a temperature above which the homogeneous solutions separates into two phases: a dilute phase containing a low surfactant concentration and coacervate phase containing a very high surfactant concentration (e.g., 20 wt% surfactant). In this work, foam formation was measured for the dilute phase, the coacervate, and the mixed solution using the Ross-Miles method for nonylphenol polyethoxylates with 8, 9, or 10 ethylene oxide moieties per molecule. The dilute phase showed no antifoam effect above the cloud point if the coacervate phase was not present, and the coacervate phase foamed little in the absence of the dilute phase. The coacervate phase acts as an oil droplet antifoam to the dilute phase. From surface and interfacial tension data, entering, spreading, and bridging coefficients for this system make it appear probable that the coacervate phase is forming bridges across the film lamellae of the dilute-phase foam and acting to suppress foam formation through the bridging mechanism.     

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.     

The Clouding of an Anionic Surfactant in Acid Solution: Mechanistic and Analytical Implications

The clouding of sodium dodecyl sulfate (SDS) in strongly acidic solutions has seen analytical use, but its mechanism has generally been misinterpreted. In the present work it was found that as SDS slowly hydrolyzes to form dodecanol, the solution passes through a series of compositions at which the aggregation of surfactant is promoted by nucleation onto traces of insoluble dodecanol. This occurred at concentrations well below the critical micelle concentration of SDS and resulted in mixed aggregates that grew to macroscopic size, giving the solution a cloudy appearance. The increasing dodecanol content eventually caused coalescence into a coacervate phase which evolved into a solid layer of dehydrated dodecanol. The process, which continued over an extended period, depended on the temperature and the concentration and type of acid used. The early stages of SDS aggregation were monitored through the I ₁/I ₃ ratio of pyrene fluorescence, which confirmed the existence of micelle-like aggregates at low surfactant concentration. The mixed SDS/dodecanol systems formed in acid hydrolysis were mimicked in neutral solution by combining the appropriate amounts of SDS, dodecanol, and NaCl. Clouding and the formation of a coacervate phase generally proceeded in a similar manner in these solutions.     

Solubilization of model stratum corneum liposomes by quaternary ammonium surfactants

The solubilizing interactions of a series of quaternary ammonium surfactants [alkyl chain lengths C-12 (DoTAB), C-14 (TeTAB), and C-16 (HeTAB)] with liposomes formed by a mixture of lipids modeling the stratum corneum (SC) lipid composition (40% ceramides, 25% cholesterol, 25% palmitic acid, and 10% of cholesteryl sulfate) were investigated. Surfactant/lipid molar ratios (Re) and bilayer/aqueous phase partition coefficients (K) were determined by monitoring changes in static light scattering of the system during solubilization. Free surfactant concentration was always similar to the critical micelle concentration (CMC). A general assumption for phosphatidylcholine (PC) liposomes suggests that the free surfactant concentration must reach CMC for solubilization to occur. This assumption can be applied to SC liposomes in this study, and indicates that liposome solubilization was mainly driven by mixed micelle formation. The Re and K parameters fell as the surfactant alkyl chain length decreased or CMC increased. Thus, a higher CMC corrsponds to an increased ability of these surfactants to saturate or solubilize SC liposomes and to a lower degree of partitioning into liposomes or affinity with these bilayer structures. The overall balance of these opposing tendencies shows that TeTAB had the highest effectiveness with respect to the saturation and solubilization of SC structures in terms of total surfactant needed to produce these effects. Different trends in surfactant interaction with SC liposomes were observed when comparing Re and K parameters with those for PC liposomes. Because SC liposomes were more resistant to the surfactant action, the affinity of surfactants with these bilayer structures was higher in all cases.