Micellar extraction preconcentration of barium with phases of nonionic surfactants at the cloud point

The micellar extraction of barium with phases of nonionic surfactant Triton X-100 was studied in the presence of aliphatic monocarboxylic acids, crown ethers, and Carboxyarsenazo and its mixtures with cetylpyridinium chloride and octylamine. It was shown that the complete extraction of barium into the micellar phase was attained using Carboxyarsenazo and cationic surfactants in the presence of octylamine through the formation of a ternary hydrophobic complex. The conditions for the determination of the atomic absorption of barium in water with preconcentration into the nonionic surfactant phase at the cloud point temperature were developed.     

Mixed micelle behavior of Pluronic L64 and Triton X-100 with conventional and dimeric cationic surfactants

The mixed micellar properties of a triblock copolymer, Pluronic L64, (EO)13(PO)30(EO)13, and a nonionic surfactant, Triton X-100, in aqueous solution with conventional alkyl ammonium bromides and their dimeric homologues were investigated with the help of fluorescence and cloud point measurements. The composition of mixed micelles and the interaction parameter, beta, evaluated from the critical micelle concentration (cmc) data for different mixtures using Rubingh's and Motomura's theories are discussed. It has been observed that the mixed micelle formation between monomeric/dimeric alkyl ammonium bromides and L64 was due to synergistic interactions which increase with the increase in hydrophobicity of the cationic component. On the other hand, synergistic mixing was observed in the mixed micelles of Triton X-100 and monomeric cationic surfactants, the magnitude of which decreases slightly with the increase in hydrophobicity of the cationic component. Antagonistic interactions were observed in the case of Triton X-100 and dimeric cationic surfactants.     

Studies on the molecular interaction of safranin-T with surfactants

The spectrophotometric studies of safranin-T (Saf-T) dye in an aqueous solution containing three different types of surfactants such as CTAB (cationic), SLS (anionic) and Triton X-100 (TX-100), Tween-20, 40, 60 and 80 (nonionic) show that Saf-T forms a 1:1 molecular complex with TX-100, Tweens and SLS. Such a type of interaction is absent in Saf-T and CTAB. The thermodynamic and spectrophotometric properties of these complexes suggest that Saf-T forms a strong charge transfer (CT) complex with TX-100 and Tweens, whereas the interaction of Saf-T with SLS is coulombic in nature. Photogalvanic and photoconductometric studies also support the above interactions. In addition to this, the electron-donating ability among the nonionic surfactants i.e. TX-100 and Tweens towards dye, role of surface in CT interaction, the site of CT interaction and the intensity and stability of CT interaction between Saf-T and nonionic surfactants have been pointed out.     

Interactions between nonpolar surfaces in mixed solutions of cationic and nonionic surfactants

The interaction energy between hydrophobic SiO₂ particles in aqueous solutions of a cationic surfactant (dodecylpyridinium bromide, DDPB), a nonionic surfactant (Triton X-100, TX-100), and their mixed solutions was measured as a function of concentration. Synergism has been observed in mixed surfactant solutions: the surfactant concentration required for achieving the set interaction energy in the mixed solutions was lower than in the solutions of the individual surfactants. The molecular interaction parameters in surfactant mixtures were calculated using the Rosen model. Chain-chain interactions between nonionic and cationic surfactants were suggested as the main reason for the synergism.     

Indirect determination of surfactants by adsorptive stripping voltammetry

The effect of some anionic, cationic and nonionic surface-active substances on the suppression of adsorptive accumulation of the bis(dimethylglyoximato)nickel(II) complex, Ni(DMG)₂, is described. Competitive adsorption of surfactants can be used to determine surfactants commonly used in commercial detergents. Triton X-100 shows the most pronounced effect on the peak height. The shape of the calibration curve depends on the concentration and on the adsorption potential. Highest sensitivity is obtained when equilibrium between Ni(DMG)² in solution and on the electrode surface is attained rapidly. Under these conditins, the detection limit is 1 μ 1^?1 Triton X-100. Calibrations are linear over 1–2 orders of magnitude.     

Clouding and phase behavior of nonionic surfactants in hydrophobically modified hydroxyethyl cellulose solutions

Clouding phenomena and phase behaviors of two nonionic surfactants, Triton X-114 and Triton X-100, in the presence of either hydroxyethyl cellulose (HEC) or its hydrophobically modified counterpart (HMHEC) were experimentally studied. Compared with HEC, HMHEC was found to have a stronger effect on lowering the cloud point temperature of a nonionic surfactant at low concentrations. The difference in clouding behavior can be attributed to different kinds of molecular interactions. Depletion flocculation is the underlying mechanism in the case of HEC, while the chain-bridging effect is responsible for the large decrease of cloud point for HMHEC. Composition analyses for the formed macroscopic phases were carried out to provide support for associative phase separation for the case of HMHEC, in contrast to segregative phase separation for HEC. An interesting three-phase-separation phenomenon was reported in some HMHEC/Triton X-100 mixtures at high surfactant concentrations.     

Correlation between surface free energy of quartz and its wettability by aqueous solutions of nonionic, anionic and cationic surfactants

The measurements of the advancing contact angle for water, glycerol, diiodomethane and aqueous solutions of Triton X-100 (TX-100), Triton X-165 (TX-165), sodium dodecyl sulfate (SDDS), sodium hexadecyl sulfonate (SHDS), cetyltrimethylammonium bromide (CTAB) and cetylpyridinium bromide (CPyB) on quartz surface were carried out. On the basis of the contact angles values obtained for water, glycerol and diiodomethane the values of the Lifshitz–van der Waals component and electron-acceptor and electron-donor parameters of the acid–base component of the surface free energy of quartz were determined. The determined components and parameters of the quartz surface free energy were used for interpretation of the influence of nonionic, anionic and cationic surfactants on the wettability of the quartz. From obtained results it was appeared that the wettability of quartz by nonionic and anionic surfactants practically does not depend on the surfactants concentration in the range corresponding to their unsaturated monolayer at water–air interface and that there is linear dependence between adhesional and surface tension of aqueous solution of these surfactants. This dependence for TX-100, TX-165, SDDS and SHDS can be expressed by lines which slopes are positive. This slope and components of quartz surface free energy indicate that the interaction between the water molecules and quartz surface might be stronger than those between the quartz and surfactants molecules. So, the surface excess of surfactants concentration at the quartz–water interface is probably negative, and the possibility of surfactants to adsorb at the quartz/water film–water interface is higher than at the quartz–water interface. This conclusion is confirmed by the values of the adhesion work of “pure” surfactants, aqueous solutions of surfactants and water to quartz surface. In the case of the cationic surfactants the relationship between adhesional and surface tension is more complicated than that for nonionic and anionic surfactants and indicates that the relationship between the adsorption of the cationic surfactant at water–air and quartz–water interface depends on the concentration of the surfactants in the bulk phase.     

A general chemiluminescence method for the determination of surfactants based on its quenching effect on the luminol-NaIO4-cyclodextrin reaction

Here we report that all types of surfactant could be simply and sensitively determined, by directly quenching the chemiluminescence (CL) between luminol and NaIO4 in a basic solution containing one polyhydroxyl compound such as cyclodextrin (CD), glucose or glycerol. This specific quenching effect was attributed to the change of the microenvironment of the CL reaction, caused by the addition of various surfactants. Based on this fact, the potential use of this CL reaction was exemplified by the cationic surfactant CTMAB, anionic surfactant SDS and non-ionic surfactant Triton X-100. It was found that the measurable range of CTMAB, SDS and Triton X-100 were 4.0 x 10(-6)-4.0 x 10(-4) M by using a basic CD-luminol-NaIO4 CL reaction. With our simple setup, CTMAB, SDS and Triton X-100 were detectable at a concentration as low as 2 microM. Overall, this new CL reaction is quite promising for the post-column determination of surfactant mixtures.     

Use of surfactant-mediated phase separation (cloud point extraction) with affinity ligands for the extraction of hydrophilic proteins

The feasibility of utilizing a zwitterionic surfactant, 3-(nonyldimethylammonio)propylsulfate, or nonionic surfactant, Triton X-114, mediated phase separation in conjunction with affinity ligands was studied for hydrophilic protein extractions. Below (or above) its critical temperature (so-called cloud point), aqueous solutions of zwitterionic (or nonionic) surfactants separate into two immiscible phases, a surfactant-rich phase and an aqueous phase. Avidin was successfully extracted into the zwitterionic surfactant-rich phase when a small amount of the affinity ligand, N- biotinoyl)dipalmitoyl- l -alpha- phosphatidyl ethanolamine, was added to the system. It was not possible to extract hexokinase into the surfactant-rich phase of the nonionic surfactant, Triton X-114, even if a considerable amount of octyl-beta-d-glucoside was added to the solution as an affinity ligand. In contrast, the use of the zwitterionic surfactant and octyl-beta-d-glucoside as an affinity ligand proved to be effective for the extraction of hexokinase. The hexokinase extraction efficiency was found to depend upon the solution pH and the concentration of the affinity ligand in the system. The results clearly indicate that hydrophilic proteins can be successfully extracted with surfactant mediated phase separations (cloud point extractions) via use of the zwitterionic surfactant, 3-(nonyldimethylammonio)propylsulfate, and appropriate affinity ligands. Some advantages of zwitterionic surfactants in such extractive processes relative to that of nonionic surfactants are delineated.     

Effects of surfactants on complex formation of CuII with 2-dimethylaminomethylphenol

The effect of cationic (cetyltrimethylammonium bromide) and nonionic (Triton X-100) surfactants on the complex formation of Cu^II with a bifunctional ligand, 2-dimethyl-aminomethylphenol, in water was studied by spectrophotometry, pH-metry, and mathematical modeling of equilibria in solutions. The character of complex formation depends on the nature and concentration of surfactants. The dependence of complex formation constants on the concentration of surfactants is discussed.Translated fromIzvestiya Akademii Nauk. Seriya Khimicheskaya, No. 8, pp. 999–2002, August, 1996.     

Adsorption of cationic and nonionic surfactants on a SiO<Subscript>2</Subscript> surface from aqueous solutions: 1. Adsorption of dodecylpyridinium bromide and Triton X-100 from individual solutions

Adsorption of cationic surfactant dodecylpyridinium bromide and nonionic surfactant Triton X-100 from aqueous solutions on the surface of SiO₂ particles is studied at various pH values (3.6, 6.5, and 10). The data on the adsorption are compared with the data on the wetting of quartz plates by solutions of these surfactants. Adsorption of both studied surfactants on the SiO₂ surface is greatly dependent on solution pH. The mechanism of adsorption of the cationic surfactant is shown to be changed when passing to the alkaline pH region. Triton X-100 does not demonstrate a substantial change in the adsorption mechanism in the pH range from 3.6 to 10.__________Translated from Kolloidnyi Zhurnal, Vol. 67, No. 2, 2005, pp. 274–280.Original Russian Text Copyright © 2005 by Kharitonova, Ivanova, Summ.     

Flow-injection system for determination of critical micelle concentrations of ionic and nonionic surfactants

A practical technique is presented for the rapid, accurate determination of the critical micelle concentrations (CMCs) of ionic and nonionic surfactants. The precision, speed and instrumental simplicity of a flow-injection system are combined with a gradient chamber and flow-through conductance and absorbance detection to produce a system capable of determining the CMC of surfactant solutions in less than 30 min. The exponential response gradients from the resulting system are monitored by a chart recorder and simple manual calculations yield the CMC. The validity of the technique is verified by determination of the CMC values for both ionic (cetyltrimethylammonium bromide and chloride and sodium dodecyl sulfate) and nonionic (Brij-35, Brij-56, Brij-99, Triton X-100) surfactants. The proposed technique does not require the extensive solution preparation, repetitive measurements, complex instrumentation and data manipulation typical of other methods for determining CMCs.     

Adsorption of cationic and nonionic surfactants on a SiO<Subscript>2</Subscript> surface from aqueous solutions: 2. Adsorption of dodecylpyridinium bromide and Triton X-100 from mixed solutions

Adsorption of cationic (dodecylpyridinium bromide) and nonionic (Triton X-100) surfactants from their mixed aqueous solutions on a SiO₂ surface at pH 3.6, 6.5, and 10 is studied by the UV spectroscopy, capillary zone electrophoresis, and wetting measurements. It is shown that the adsorption of cationic and nonionic surfactants from mixed solutions is accompanied by synergistic effects manifesting themselves as an enhanced adsorption of both surfactants compared to their adsorption from individual solutions. The effect of second component becomes most pronounced under conditions when differences in adsorption abilities of individual surfactants are rather large (at pH 3.6 and 10). It is shown that the adsorption of surfactants from mixed solutions can be controlled by the adsorption ability of components via the variations in solution pH.__________Translated from Kolloidnyi Zhurnal, Vol. 67, No. 2, 2005, pp. 281–287.Original Russian Text Copyright © 2005 by Kharitonova, Ivanova, Summ.     

Interaction of nonionic surfactants with copolymer microgel particles of NIPAM and acrylic acid

Binding of the nonionic surfactants Triton X-100 and Triton X-405 onto linear copolymers of N-isopropylacrylamide (NIPAM) and acrylic acid and to cross-linked microgel particles of similar composition but differing in their cross-link densities has been studied. The binding capacities vary for each of these polymeric systems, being smallest for the linear copolymer. The binding is also significantly less in all cases for the more hydrophilic surfactant, namely, Triton X-405. By comparing estimates of the pore or "cage" size within the microgel particles with the dimensions of the free micelles in solution, it is concluded that micelles of Triton X-100 form within the microgel particles more readily for the lower cross-linked microgel particles. However, micelles do not form as easily inside either microgel for Triton X-405. The swelling/deswelling behavior of each of the two microgels, in the presence of the surfactants, has been explained in terms of their relative binding behavior and how this contributes to the osmotic pressure difference inside and outside the microgel particles and also in terms of micelle "bridging" of the polymer network, causing shrinkage.     

Equilibrium contact angles as a function of the concentration of nonionic surfactants on quartz plate

The contact angles of aqueous solution of Triton X-100 and Triton X-305 for airwater-quartz and cyclohexane-water quartz systems have been studied. It has been found that the equilibrium contact angle (measured through water) against quartz is increased by the addition of small amounts of nonionic surfactants, but beyond a certain concentration the angle decreases again. Based on the bilayer adsorption model on quartz/water interface, the experimental results can be explained.     

Effect of Surfactants and Ionic Strength on Dissociation of Hydrochlorides of Phenothiazine Derivatives

Abstract

A study of the effect of the anionic surfactant dodecyl sulfate, the cationic surfactant carbethoxypentadecyl trimethyl ammonium bromide (Septonex), nonionic surfactant p-octyl phenyl polyoxyethylene (Triton X-100), and a strong electrolyte (KBr) on the dissociation of the hydrochlorides of two derivatives of phenothiazine (diethazine and fluphenazine) was made. It was found that sodium dodecyl sulfate increases the pKa value, whereas Septonex and Triton X-100 decrease this value. The presence of KBr suppresses the effect of the surfactants. A new method for the potentiometric determination of fluphenazine in an aqueous medium was proposed.     

Study on cloud points of Triton X-100-cationic gemini surfactants mixtures: A spectroscopic approach

This study investigates the effects of various cationic surfactants on the cloud point (CP) of the nonionic surfactant Triton X-100 (TX-100) in aqueous solutions. Instead of visual observation, a spectrophotometer was used for measurement of the cloud point temperatures. The values of CPs for Triton X-100 can be measured directly because TX-100 has an average number of oxyethylene units per molecule of p ≈ 9.5 and a CP = 66.0 °C. Quaternary ammonium dimeric surfactants (m-s-m, m = 10, 12, and 16, and s = 2, 6, and 10) were synthesized and used. The melting temperature T_M and the Krafft temperature T_K were measured for 1 wt% aqueous solutions of these synthesized surfactants. The melting temperature of the solid gemini surfactants increased with the carbon number of the alkyl chain. The results showed that additions of the gemini surfactants (which are infinitely miscible with water) to Triton X-100 increased the cloud point of the TX-100 solutions. All salts tested in these studies had a large effect on the CPs of nonionic surfactants due to their effect on water structure and their hydrophilicity. The effect of the alkyl chain length of the gemini surfactant on the CP of Triton X-100 is therefore more important than the spacer chain length.     

Colloidal particles derived from a complex of phosphotungstic Acid and ethoxylated surfactants

Stable, colloidal sols of submicron size were prepared by titration of aqueous solutions of alkylene oxide surfactants with phosphotungstic acid, H(3)PW(12)O(40) (PTA), followed by neutralization with ammonium or potassium hydroxide. The stoichiometry of the complex between phosphotungstic acid and the ethoxylated surfactant was determined by (1)H and (31)P NMR and was dependent upon the degree of ethoxylation. For example, in the ethoxylated octylphenol having 9-10 ethylene oxide units, Triton X-100, the mole ratio of surfactant to PTA was 4.5. In the ethoxylated octylphenol having 70 ethylene oxide units, Triton X-705, the mole ratio of surfactant to PTA was 1. Prior to nucleation of particles, phosphotungstic acid forms an apparent yellow charge transfer complex with ethoxylated alkylphenol surfactants, typified by Triton X-405. This complex is characterized by an absorption spectrum that is the sum of the spectra of Triton X-405 and PTA with a very weak shoulder at 400-500 nm. Particles were nearly monodisperse and their size was dependent on the nonionic surfactant employed, the heteropolyacid, and the rate of addition of heteropolyacid solution.     

Effects of surfactants on the adsorptive removal of basic dyes from water using an organomineral sorbent-iron humate

The sorption of basic dyes (methylene blue, malachite green, rhodamine B, crystal violet) onto a nonconventional organomineral sorbent-iron humate-was examined in the presence of various kinds of surfactants. It was found that nonionic (Triton X-100) and cationic (cetyltrimethylammonium bromide) surfactants exhibited a relatively small effect on the dye sorption. Anionic surfactants (sodium dodecyl sulfate), on the other hand, affected (in most cases) dramatically the sorption of basic (cationic) dyes. Typically, the dye sorption was enhanced in the presence of low concentrations of anionic surfactants. At high surfactant concentrations, a steep decrease in the dye sorption was observed in some systems, probably due to the formation of micelles that solubilize the dye molecules and prevent their sorption. A model describing these experimental dependencies was proposed. The sorption of basic dyes onto iron humate may be described by the pseudo-second-order kinetic equation. Diffusion processes were identified as the main mechanisms controlling the rate of the dye sorption.     

Micellar-enhanced ultrafiltration of cadmium ions with anionic–nonionic surfactants

Micellar-enhanced ultrafiltration (MEUF), a surfactant-based separation process, is promising in removing multivalent metal ions from aqueous solutions. The micellar-enhanced ultrafiltration of cadmium from aqueous solution was studied in systems of anionic surfactant and mixed anionic/nonionic surfactants. The micelle sizes and zeta potentials were investigated by dynamic light scattering measurements. The effects of feed surfactant concentration, cadmium concentration and the molar ratio of nonionic surfactants to sodium dodecyl sulfate (SDS) on the cadmium removal efficiency, the rejection of SDS and nonionic surfactants and the permeate flux were investigated. The rejection efficiencies of cadmium in the MEUF operation were enhanced with higher SDS concentration and moderate Cd concentration. When SDS concentration was fixed at 3 mM, the optimal ranges of the molar ratios of nonionic surfactants to SDS for the removal of cadmium were 0.4–0.7 for Brij 35 and 0.5–0.7 for Triton X-100, respectively. With the addition of nonionic surfactants, the SDS dosage and the SDS concentration in the permeate were reduced efficiently.