Enhanced sorption of phenanthrene on activated carbon in surfactant solution

Distribution of a hazardous hydrophobic organic compound (HOC) and a nonionic surfactant in aqueous/activated carbon systems was investigated. Phenanthrene was selected as a representative HOC and Triton X-100 as a surfactant. Three activated carbons that differed in size (Darco 20-40, 12-20 and 4-12 mesh sizes) were used in the adsorption experiments. The system was analyzed using a mathematical partitioning model and compared with intrinsic sorption of phenanthrene without the effect of sorbed surfactant. Phenanthrene was sorbed onto activated carbon in a greater amount than an estimated value by intrinsic sorption, even though surfactant molecules covered most of surfaces. The sorbed surfactant was much more effective as a sorbent for phenanthrene, in the range of 1.2-98 for effectiveness factor, than was activated carbon, particularly at high surfactant doses. We introduced surface molar solubilization ratio (MSR_s) for sorbed micelles of surfactant and mathematically estimated using effectiveness factor and available carbon fraction of activated carbon after surfactant sorption. The MSR_s for sorbed surfactant was 5-46 times higher than the MSR for micellar surfactant in bulk solution. The sorbed surfactant onto activated carbon can more effectively remove hazardous organic compounds in liquid environmental samples.     

Solubilization of model polycyclic aromatic hydrocarbons by nonionic surfactants

Solubilization of model polycyclic aromatic hydrocarbons (PAHs) by the readily biodegradable nonionic surfactants, Tergitol 15-S-X (X=7,9 and 12), consisting of mixtures of secondary ethoxylated alcohols was investigated at temperatures below their cloud points. Their solubilization capacities for phenanthrene were compared to those of three other commonly used surfactants, e.g. Triton X-100 and Tween 20 as well as Tween 80. Correlation between the micelle-water partition coefficients and the octanol-water partition coefficients in Tergitol 15-S-7 solutions indicated that the hydrophobicity of PAHs, i.e., their octanol-water partition coefficients, could be used in predicting the solubilization efficiency of PAHs by this nonionic surfactant. Effects of temperature and salinity on solubilization capacity of Tergitol 15-S-7 surfactant for phenanthrene were also investigated along with the micellar properties. The change in hydrodynamic radius and aggregation number of micelles with temperature was measured by the dynamic and static laser light scattering techniques. Results showed that increasing aggregation number and micellar size at higher temperature when cloud point is approached gives rise to the higher solubilization capacity of this surfactant. Effect of salinity on the enhancement of phenanthrene solubility was also discussed in terms of conformation changes in the micelles due to the possible coordination of sodium cations and oxygen atoms on the ethylene oxide groups of the surfactant.     

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     

Extraction of a dissolved organic contaminant from water into an aqueous surfactant solution across a microporous membrane

A novel extraction process, aqueous micellar solvent extraction (AMSE), was demonstrated. In ASME an solute is extracted from a wastewater across a microporous membrane into an aqueous surfactant solution containing micelles that solubilize the solute. The membrane retains the surfactant micelles in the aqueous micellar solvent. ASME was carried out in hollow fiber ultrafiltration modules with benzoic acid as the solute and a fatty amine ethoxylate surfactant. Flowing the micellar solvent through the fibers and the wastewater outside gave good extraction and low contamination of the treated water by surfactant. The major resistance to extraction of solute was diffusion across the wall of the hollow fiber.     

Synthesis of amphiphilic polyurethane nanonetwork particles and their application for the soil‐washing process

Nanosized amphiphilic polyurethane (APU) particles synthesized on the basis of amphiphilic urethane acrylate nonionomers could solubilize phenanthrene within their hydrophobic interiors in the same way that surfactant micelles do in the aqueous phase. At low concentrations of APU or Triton X‐100 in the aqueous phase, APU particles exhibited a greater extraction efficiency of sorbed phenanthrene than did the Triton X‐100 aqueous pseudophase. At higher APU particle and Triton X‐100 doses in aqueous solution, the extraction efficiency of the APU aqueous solution was almost same as that of the Triton X‐100 aqueous solution, even though APU particles exhibited a lower solubilizing efficiency than Triton X‐100 micelles in the absence of aquifer soil. This was because APU particles have a relatively low degree of sorption on aquifer sand because of their chemically crosslinked structure. APU particles could be also recovered at a rate of 100% through an ultrafiltration process at a greater pore size of the separation membrane, which would make soil washing with APU particles more economical and useful in practical applications. © 2002 Wiley Periodicals, Inc. J Appl Polym Sci 87: 1666–1677, 2003     

苯酚在浊点萃取中凝聚层相的增溶规律

采用分光光度法测定了苯酚在非离子表面活性剂单相胶束溶液中和在非离子表面活性剂两相浊点萃取时凝聚层相中的增溶结果.实验表明：溶质在凝聚层相的增溶与表面活性剂形成胶束的结构有关.当凝聚层相的表面活性剂形成正相胶束时,溶质在凝聚层相的增溶规律和在表面活性剂胶束溶液中的增溶规律一致;当凝聚层相的表面活性剂形成反相胶束时,溶质在凝聚层相和在溶液相的浓度关系可理解为在这两种溶剂之间的分配随着凝聚层相的含水率逐渐降低趋近于一定值,溶质的分配系数也趋近于一定值.     

反胶团萃取蛋白质特性的研究

实验将一种阴离子表面活性剂（AOT）和一种阳离子表面活性剂（Aliquat336）分别溶于异辛烷（isooctane）中，构成了两种不同的反胶团体系．通过用两种不同的反胶团溶液萃取六种蛋白质的实验，研究了水相pH值及离子强度对反胶团体系中水含量Wo和蛋白质萃取率影响的规律．实验发现不论哪种反胶团体系，水相pH值对Wo的影响都不大，但pH值却对蛋白质萃取率有很大的影响，对AOT反胶团体系而言，随着pH值的降低，蛋白质的萃取率升高；对Aliquat336反胶团体系而言，随着水相pH值的降低，蛋白质的萃取率下降．随着离子强度的增大，AOT反胶团体系的水含量大幅度地降低；而对Aliquat336体系水含量的影响很小，但水相离子强度对蛋白质萃取率的影响是相同的，随着离子强度的增大，两种体系对蛋白质的萃取率均下降。     

Hydrocarbon Extraction into Surfactant Phase with Nonionic Surfactants. II. Model

Abstract

The solubilization kinetics of an extraction process of oil with an aqueous micellar solution of a nonionic surfactant has been modeled. The model is directly related to the phase diagram, allowing a simple form which explains the main effects. The theoretical results show the adsorption process of surfactant at the phase interfaces to provide the main resistance to the mass transfer processes. The values of adsorption rates, and of some of the diffusion coefficients obtained, compare well with the earlier experimental results.     

Solubilization of fatty soils by a radiotracer technique

A technique for measurement of solubilized radiotagged triolein and tristearin fatty soils is described. By using surfactant solutions under standardized conditions of temperature and agitation, the solubilized soils are removed from emulsified materials by filtration through 0.1 and 0.01 micron-pore size of filters. The radiotagged fat is recovered by solvent extraction from the clear filtrate by salting-out under centrifugal force and is measured by conventional counting technique. The nonionic alkanol- and alkylphenol-ethylene oxide (EO) adducts solubilized up to 0.058% triolein (weight percentage at 75°C.) while anionic surfactant and sodium tripolyphosphate solubilization was negligible. These findings suggest for these nonionics that solubilization is one of the main, if not the controlling factor in the mechanism of soil removal. Nonionic solubilization was at a maximum for 10 molar EO adducts and at near cloud-point temperatures. For the same surfactant more triolein than tristearin was solubilized, possibly on account of spatial considerations. For tridecanol-10 EO at 0.25% the heat of solubilization of triolein, ΔH_s, was 15 kcal/mole while the heat of micellization of the adduct was 1.3 kcal/mole of adduct. Differences in the colloidal ion lengths of the micelles and their aggregation numbers may explain the differences in solubilization between the anionic and nonionic surfactants tested.     

微波辅助胶团提取甘草中的甘草酸和甘草甙

The feasibility of emploving non-ionic surfactant （Triton X-100） as an alternative and effective solventfor the microwave-assisted extraction of glycyrrhizic acid （GA） and liquiritin （LQ） from licorice root was studied.The optimal extraction parameters based on the microwave-assisted micellar extraction technique were determined.Under the optimal conditions, i.e. 5% （by volume） Triton X-100, microwave-assisted extraction for 3--5min at 373K, the percentage extraction of active ingredients reached the highest value. The preconcentration tactor for GA and L＇Q （about 13.5） and the extraction efficiency for these two ingredients approached 100% showed the coupling of microwave-assisted extraction and cloud-point extraction could be employed as a new and. effective techniquefor the rapid extraction and preconcentration of pharrnacologically active ingredients from medicinal plants SUCh aslicorice root without disturbing chromatographic analysis.     

Ethoxy Carboxylate Extended Surfactant: Micellar,Adsorption and Adsolubilization Properties

The micellar, adsorption, and adsolubilization properties of a novel ethoxy carboxylate extended surfactant are measured and compared to an extended sulfate surfactant. The critical micelle concentration (CMC) of the ethoxy carboxylate extended surfactant is measured to be 0.02 mM while it is 0.07 mM for the extended sulfate surfactant. Adsorption and adsolubilization studies are carried out on alumina oxide surfaces. The extended sulfate surfactant has a higher maximum adsorption capacity onto the aluminum than the ethoxy carboxylate extended surfactant (0.47 vs. 0.14 mmol/g, respectively). For adsolubilization, the extended sulfate surfactant shows a slightly higher phenanthrene adsolubilization compared to the ethoxy carboxylate extended surfactant (log K_adm of 6.15 vs. 5.71, respectively). In contrast, for solubilization, the ethoxy carboxylate extended surfactant exhibits higher phenanthrene solubilization capacities than the extended sulfate surfactant (log K_mic of 5.61 vs. 5.42, respectively). Relative to surfactant loss from the solid surface, the ethoxy carboxylate extended surfactant shows a higher desorption capacity as compared to the extended sulfate surfactant. From these measurements, the ethoxy carboxylate extended surfactant has better properties for micellar applications (lower CMC, higher K_mic), while the extended sulfate surfactant has better properties for admicellar applications (higher q_max and K_adm values, and less desorption).     

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.     

Solubilization as a Separation Process

Abstract

In this paper a separation process for hydrocarbon molecules is suggested, based on solubilization in aqueous solutions by surfactant micelles. A molecular thermodynamic approach to solubilization is formulated which relates the extent of solubilization and the selectivity to the structure and properties of the surfactant and of the solubilizate molecules. An evaluation of the solubilization characteristics of benzene and hexane in aqueous solutions of non-ionic octyl glucoside, anionic sodium dodecyl sulfate and cationic cetyl pyridinium chloride is made and solubilization phase diagrams for the above systems are constructed. These diagrams indicate the formation of micelles at concentrations which are lower than the critical micelle concentration of the surfactant alone. The calculations predict, for all three surfactants, preferential solubilization of (aromatic) benzene compared to (aliphatic) n-alkanes. The preferential solubilization of benzene is caused by its smaller molecular volume and lower interfacial tension against water. Preliminary experimental results using cetyl pyridinium chloride as surfactant and an equimolar binary mixture of hexane and benzene as solubilizates indicate a selectivity of over 7 for benzene compared to hexane, and a ratio of about one molecule of benzene solubilized for every surfactant molecule in the micelle.     

Amino acid solubilization in cationic reversed micelles: factors affecting amino acid and water transfer

The aim of this work is to investigate the driving forces involved in amino acid solubilization in cationic reversed micelles, and to determine in which way different parameters affect the reversed micellar structure and amino acid solubilization, in order to select the best conditions to optimize amino acid extraction. To this end, extraction equilibrium experiments were performed using different experimental conditions and three amino acids with different structures: aspartic acid – a hydrophilic amino acid, phenylalanine – a slightly hydrophobic amino acid, and tryptophan – a hydrophobic amino acid. The study of the effect of amino acid related parameters, such as pH and the initial amino acid concentration in the aqueous phase, and the effect of parameters that influence the reversed micellar structure, such as surfactant concentration, ionic strength and co‐surfactant concentration, provides useful information about the driving forces involved, solute–micelle interfacial interactions and solute location in the cationic system trioctylmethylammonium chloride (TOMAC)/hexanol/n‐heptane. These parameters can be adjusted to optimize amino acid extraction. It is shown that amino acids with the same isoelectric point can be selectively separated by exploring the different interactions they establish with the reversed micellar interface. © 1999 Society of Chemical Industry     

The temperature dependence of micellar solubilization

The temperature dependence of micellar solubilization was determined in the 180°–140°F. temperature range by using a dye solubilization technique with built and unbuilt solutions of three high-eloud point, commereial surfactants, one anionic of the alkylaryl sulphonate type and two types of nonionic agents. It was found that the logarithm of solubilization in both built and unbuilt solutions was directly proportional to temperature (solubilization was an exponential function of temperature) and that the log solubilization-temperature slopes of the built and unbuilt solutions of each surfactant were approximately parallel.     

Temperature‐induced surfactant‐ mediated pre‐concentration of uranium assisted by complexation

Cloud‐point extraction (CPE) was used with lipophilic chelating agent to extract uranium(VI) from aqueous solutions. The methodology used is based on the formation of metal complexes soluble in a micellar phase of a non‐ionic surfactant, Triton X‐114. The metal ions complexes are then extracted into the surfactant‐rich phase at a temperature above the cloud‐point temperature. The influence of surfactant concentration on extraction efficiency was studied and the advantage of adding 8‐hydroxyquinoline (8HQ) as lipophilic chelating agent was evidenced. High extraction efficiency was observed, indicating the feasibility of extracting U(VI) using CPE. This study describes a four‐step process—(1) extraction, (2) thermo‐induced phase splitting, (3) back‐extraction and (4) second phase splitting—for the recovery of uranium from water. In our conditions, the extraction yield is quantitative and the concentration factor obtained is superior to 100. After stripping with a diluted nitric acid solution (pH < 1), the system can be recycled through a new four‐step cycle. Copyright © 2006 Society of Chemical Industry     

Effects of various hydrocarbons on micellar growth

The effect of aliphatic and aromatic hydrocarbons on surfactant micellar growth has been investigated by viscosity measurements at 40°C. Aqueous and aqueous KBr (0.1 M) solutions of 0.1 M cetylpyridinium bromide (CPB) showed that the viscosity behavior changed substantially in the presence of KBr. This is attributed to favorable conditions produced by KBr that assist micellar growth by addition of hydrocarbons. Reasons for the effectiveness of the solubilized hydrocarbons are suggested and supported by theoretical arguments. The causes of viscosity decrease at higher aromatic hydrocarbon concentrations are also explained. Micellar growth with soluble aromatic/aliphatic hydrocarbons could also be initiated if a moderate salt concentration is present in CPB micellar solutions. The chainlength, solubilization site, and molar volume of the soluble hydrocarbons all affect the bulk viscosity of the solution. Such surfactant and hydrocarbon combinations may find use in micellar-enhanced ultrafiltration of benzene and its derivatives, but it should be kept in mind that micellar shape may change and be more curved at higher benzene derivative concentrations.     

聚合物反胶团萃取研究(Ⅰ)萃取平衡与萃取动力学特性

从聚合物胶团萃取和反胶团萃取的特性分析出发,提出了聚合物反胶团萃取的概念.采用PEO-PPO型嵌段共聚物和有机溶剂组成的聚合物反胶团溶液萃取不同浓度的苯酚水溶液,研究聚合物反胶团萃取平衡和萃取动力学特性.结果表明,随聚合物PPO含量的增加,分配系数和总传质系数都增大;随聚合物浓度的增大,分配系数和总传质系数亦增大;助表面活性剂的加入可以促进聚合物反胶团的增溶作用.     

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.     

有机溶剂萃取加拿大油砂应用研究

介绍了溶剂作为萃取剂分离油砂的技术,溶剂萃取油砂过程包含两个阶段:沥青相向溶剂的溶解过程和沥青、溶剂与砂粒的分离过程。考察了单一溶剂甲苯、丙酮、乙酸乙酯和甲苯/正庚烷、丙酮/正庚烷、乙酸乙酯/正庚烷组成的复合溶剂体系在相同条件下对油砂沥青的萃取率,在此基础上进一步对比了不同溶剂体系对沥青四组分饱和分、芳香分、胶质和沥青质的萃取效果,同时考察了不同浓度的沥青-溶剂溶液的表面张力,结果表明在油砂萃取过程中沥青-溶剂体系的表面张力主要取决于所选溶剂的种类,而沥青的浓度对溶液表面张力的影响不大。混合溶剂体系甲苯/正庚烷、丙酮/正庚烷、乙酸乙酯/正庚烷相比纯溶剂萃取率较高,其沥青溶液表面张力较低,是良好的分离油砂溶剂体系。