Aqueous Solutions Of Nonionic Surfactants Research Articles

Synthesis and Characterization of MSU-2 for CO2 Adsorption

The advancement of adsorption technology is highly dependent on the characteristics of the adsorbents used. However, the commonly used one-dimensional (1D) MCM-41 and two-dimensional (2D) SBA-15 were found to induce gas diffusion difficulty. With this, MSU-2 was introduced as it shows high potentiality to be employed as CO2 adsorbent due to its excellent properties such as the highly interconnected three-dimensional (3D) wormhole-like framework structure as well as large specific surface area, total pore volume and pore size. The focus of the current study focuses on the synthesis of MSU-2 and the investigation on the CO2 adsorption capacity of the synthesized MSU-2 at various temperatures and pressures. The preparation of the MSU-2 was achieved by fluoride-assisted two-step process of solution precipitation method involving the addition of tetraethylorthosilicate (TEOS) to the acidified aqueous solution of nonionic surfactant, Triton X-100. The resultant MSU-2 was characterized by SEM, TEM, SAP analyser, XRD, FTIR spectrometer and TGA. The analyzed results showed that MSU-2 with desired features was successfully synthesized. The CO2 gas adsorption studies of the MSU-2 was demonstrated at different temperatures (25 °C and 85 °C) and different pressures (1 bar and 5 bar) to study the effect of temperatures and pressures on the CO2 adsorption capacity of the MSU-2. The highest CO2 adsorption capacity of the MSU-2 was found to be 0.98 mmol-CO2/g-adsorbent when the operating conditions were set at 25 °C and 5 bar. This adsorption experiment also deduced that low adsorption temperature and high operating pressure promote adsorption process which give higher CO2 adsorption capacity.

Optical Activity of Triton X-100 Micelles in Aqueous Solutions

Polarimetry is used to study the optical activity of colloidal aqueous solutions of nonionic surfactant (NS) Triton X-100. It is found that these solutions rotate the plane of polarization to the right. It is shown that a change in the concentration of nonionic surfactants alters the structure of micelles. It is found that the transition to a continuous hexagonal mesophase is accompanied by a stepwise change in optical rotation.

Vapor bubble–bubble penetration during subcooled pool boiling in a nonionic surfactant aqueous solution

Boiling is encountered in industrial processes as an effective heat transfer method. It generates vapor to remove a large amount of heat. The evolution of vapor bubbles in a boiling liquid, especially the growth of bubbles, is one of the parameters that determine the heat transfer strength of a heating surface. The growth process of bubble is complicated due to many physical or chemical factors. Here, for the first time, we report a new phenomenon of vapor bubble–bubble interaction process (a bubble interacts with its neighboring one(s) generated at the same nucleation site) during pool boiling aided by a nonionic surfactant. The different bubble interactions are defined as bubble–bubble penetration, bubble–bubble piercing, and double penetrations. It is motivated by microbubble emission from heater in subcooled pool boiling. Bubble dynamics in aqueous surfactant solution was visualized and analyzed. Much attention was paid on the vapor bubble generation, growth, and interaction in the presence of surfactant. It is worth noting that the bubble penetration frequently occurs in the current conditions. The findings are of fundamental and practical relevance, and in the hope to contribute to better understanding of surfactant-aided boiling mechanism.

Bubble behaviors during subcooled pool boiling in water and nonionic surfactant aqueous solution

A visualization study of the bubble behavior in pool boiling of ultra-pure water and surfactant aqueous solution (Triton X-114) under different heat fluxes was performed, using a narrow transparent bare FTO heating surface with various subcooling degrees of 5°C, 25°C and 35°C, respectively. It is shown that with the decrease of liquid subcooling, bubble coalescence in ultra-pure water becomes obvious. Whilst with the increase of liquid subcooling, the bubble surface gets rough and unstable. In contrast, a newly discovered phenomenon of bubble-bubble (BB) penetration occurs in the surfactant solution under the same working condition as that in water. BB penetration behavior is a bubble interaction without coalescence. This bubble behavior is believed to be the results of micro-convection due to the shrinkage of the bubble root, and the Marangoni effect due to the surface tension gradient. Combination of Marangoni effect and bubble surface movement causes the surfactant molecules to aggregate toward the bubble root, and it effectively promotes the nucleation of the next bubble. Owe to the rapid growth of newly nucleated bubbles, the bubble-bubble penetration and piercing behaviors happen during the growth stage. The newly nucleated bubble partially accelerates the first bubble departure, also interacts with the first bubble by forming a tiny vapor channel. This phenomenon should be one of the reasons of enhanced heat transfer using surfactant solutions.

Plotting a nature-friendly separation process for recovering volatile fatty acids

The segregation capacity of cholinium bitartrate (N1112OHC4H5O6) in aqueous solutions of biodegradable non-ionic surfactants belonging to Triton family (Triton X-100 and Triton X-102) has been firstly addressed. The influence of temperature on the separation potential was analysed by carrying out the binodal curves and tie-lines from 293.15 K to 323.15 K. The immiscibility data were modelled by several empirical equations, and the tie-lines were adequately correlated by Othmer-Tobias, Bancroft and Setschenow models. Finally, the extraction capacity of the proposed biocompatible segregation agent was demonstrated for the first time in volatile fatty acids (formic acid, acetic acid, propionic, and butyric acid), recording very high levels of extraction when high surfactant concentrations are employed.

Organic superhydrophobic coatings with mechanical and chemical robustness

Abstract

Towards the use of eco-friendly solvents as adjuvants in remediation processes

Abstract The growing social concern regarding the use of more environmentally friendly processes is compelling the search of more biocompatible solvents able to overcome the drawbacks associated to the conventional ones. Thus, in this work, a Deep Eutectic Solvent (cholinium chloride:urea) was demonstrated to act as salting out agent in aqueous solutions of a model non-ionic surfactant (Triton X-100). Thus, the immiscibility region was thoroughly mapped in a range of temperatures, from T 293.15 to 323.15 K. The experimental data for each solubility curves were fitted to different empirical models based on exponential and polynomial equations. Furthermore, Othmer-Tobias and Bancroft equations have been used to correlate the tie-line data, and to provide a clearer picture of the role of these solvents as phase promoters in surfactants solutions. Finally, the extraction capacity of this system at 303.15 K was assessed for removing textiles dyes from aqueous streams, in order to demonstrate the suitability of DESs to be used as adjuvants in the remediation of industrial effluents.

Temperature Effect on the Adsorption and Volumetric Properties of Aqueous Solutions of Kolliphor®ELP.

Density, viscosity and surface tension of Kolliphor® ELP, the nonionic surfactant aqueous solutions were measured at temperature T = 293–318 K and at 5K interval. Steady-state fluorescence measurements have been also made using pyrene as a probe. On the basis of the obtained results, a number of thermodynamic, thermo-acoustic and anharmonic parameters of the studied surfactant have been evaluated and interpreted in terms of structural effects and solute–solvent interactions. The results suggest that the molecules of studied surfactant at concentrations higher than the critical micelle concentration act as structure makers of the water structure.

Mixed micelles formed by biological surfactant sodium deoxycholate and nonionic surfactants in aqueous solution

The interaction between biological surfactant sodium deoxycholate (NaDC) and nonionic surfactants polyoxyethylene (n) nonylphenol ether (NPn) for the formation of micelles in aqueous solution were investigated. Surface tension, interfacial dilational viscoelasticity, and transmission electron microscopy (TEM) were characterized to systematically study the interaction between NaDC and NPn in buffer solution. At last, the mechanism of the interaction between NPn and NaDC were analyzed. The surface tension results show that the interaction between NaDC and NPn was displayed synergism action. The composition of the mixed systems has been estimated on account of the regular solution theory, Clint’s equation, Rubingh theory and Rosen theory. The surface dilational rheology provided abundant effective information on the feature of adsorbed layers. From the oscillating barrier measurements, the peak values of the dilational modulus moved to lower concentrations in NaDC/NPn binary system compared to single surfactant. The dilational elasticity of the binary system decreased distinctly on the basis of the rigid structure of NaDC. The interaction of these two substances was proved directly by TEM images, that the boundaries of the aggregates are clearer due to the protection of NPn molecules. The new complex systems have potential application in environmental protection.

Solubilizing Potential of Ionic, Zwitterionic and Nonionic Surfactants Towards Water Insoluble Drug Flurbiprofen

Quite a high percentage of newly discovered drugs are discarded due to their low aqueous solubility and variable bioavailability. Therefore, it is necessary to explore new methodologies for increasing the aqueous solubility of such drugs. Several procedures have been proposed for this purpose, including salt formation, particle size reduction or using surfactants. In this report, we have improved the aqueous solubility of flurbiprofen by employing aqueous solution of anionic (SDS, SDBS), cationic (DTAB, CTAB, TTAB), non-ionic (Triton X-100 and Triton X-114 and DDAO) and zwitterionic DDAPS surfactants. It is concluded that all of the surfactants increased the solubility of flurbiprofen which increased with the increasing surfactant concentration. The reason behind such a trend was that the drug is partitioned between micelles and the aqueous phase. An increase in aqueous solubility of the drug was correlated with the (molar) solubilization ratio (χ), partition coefficient of drug (KM) between micelle and water, binding constant (K1) and standard state Gibbs energy of solubilization ($$\Delta G_{\text{s}}^{\text{o}}$$) of the drug in the micelles. The order of drug solubilization in nonionic and zwitterionic surfactants was found as Triton X-114 > Triton X-100 > DDAO > DDAPS. In the case of anionic surfactants, it was noted as SDBS > SDS, whereas cationic surfactants solubilized the drug in the order of CTAB > TTAB > DTAB. The differences in χ and log10KM are attributed to the structural features of the surfactants. The aggregation number, HLB, core volume of micelles and electrostatic interaction between drug and micelles play important roles in solubilization of drugs in micellar solutions. The nonionic surfactants proved to be better, due to their low critical micelle concentrations higher solubilization capability and nontoxic nature; they were also found to have better drug release profiles.

Adsorption of Triton X-100 in aqueous solution on activated carbon obtained from waste tires for wastewater decontamination

Adsorption of Triton X-100 non-ionic surfactant in aqueous solution on activated carbon was performed. The activated carbon was prepared from waste tires by chemical impregnation at 10, 20, 30, and 40% w·w−1 of potassium hydroxide. Two carbonization temperatures, 700 and 900° C were used with a heating rate of 2 °C·min−1 and a 3 h retention time in N2 flow of 100 mL·min−1. The carbons obtained were characterized by N2 adsorption at − 196 °C, scanning electron microscopy, infrared microscopy, thermogravimetric analysis, and titration of functional groups. In adsorption studies of Triton X-100, the amount of adsorbed Triton X-100 was characterized by High-performance Liquid Chromatography and Langmuir, Freundlich, Toth, and Redlich-Peterson models were evaluated. The solids showed an area between 42 and 528 m2·g−1 with characteristic isotherms of micro-mesoporous solids, and a pore distribution of 7.0 to 8.0 A by Dubinin-Astakov with a chemical surface having acid and basic groups. The carbon that adsorbed the most Triton X-100 was QK409 with Q0 220 mg·g−1.

Design of eco-friendly aqueous two-phase systems for the efficient extraction of industrial finishing dyes

Cholinium bitartrate (N1112OHC4H5O6) has been demonstrated to be a promising phase disengagement agent in aqueous solutions of biodegradable non-ionic surfactants belonging to Tween family. For the first time, these systems were demonstrated to be versatile tools to efficiently extract two of the most frequently used groups of dyes, like di-azo and anthraquinone dyes. To do that, the binodal curves of the aqueous two phase systems (Tween 20 or Tween 80 + N1112OHC4H5O6 + H2O) were characterized at different temperatures (between 293.2 K and 323.2 K) and ambient pressure (0.1 MPa). Besides, prior to apply these systems for dyes extraction, the tie-lines were characterized, and all the data were suitably described by empirical equations. Analysis from an environmental point of view of capacity of the proposed eco-friendly ionic liquid for the extraction of Acid Black 48 and Reactive Black 5 dyes from aqueous solutions reveals environmental and efficiency advantages when compared with conventional imidazolium-based ionic liquids.

Evaluation of Interfacial Properties of Aqueous Solutions of Anionic, Cationic and Non-ionic Surfactants for Application in Enhanced Oil Recovery

AbstractSurfactants play an important role in enhanced oil recovery by reducing the interfacial tension (IFT) between oil and water and changing the wettability of reservoir rock. Studies have been made to determine the effect of temperature, salt, alkali and polymer on IFT in the presence of anionic (SDS), cationic (CTAB) and nonionic (Tween 80) surfactants. The experimental data reveal that with increase in temperature the surface tension and IFT of the above surfactants are significantly reduced. IFT values of surfactants are also affected by the presence of polymer, alkali and salt. The results show that the addition of polymer increases the IFT as well as the contact angle of all the surfactant solutions. On the other hand, the presence of alkali in surfactant solution reduces the IFT between crude oil and water as alkali reacts with the acidic components of crude oil to form additional in-situ surfactants. It has been found that the presence of salt in an aqueous solution of different surfactants reduces IFT and contact angle as the salt increases the tendency of the surface active agents to accumulate at the interface. Sand pack flooding in presence of different chemical combinations has also been investigated. It has been found that the enhanced oil recovery by alkali-surfactant-polymer flooding is better than the corresponding surfactant and surfactant-polymer flooding.

Suitability of dihydrogen phosphate anion to salt out cholinium-based ionic liquids

The segregation capacity of cholinium dihydrogen phosphate (N1112OHDHP) in aqueous solutions of two non-ionic surfactants belonging to Triton X family (Triton X-100 and Triton X-102) was explored at different temperatures from T = (298.15 to 333.15) K. The experimental data for each binodal curve have been correlated using three empirical models based on exponential and polynomial equations. The tie-line data were suitably described by applying the Othmer-Tobias and Bancroft models. The data obtained demonstrated the great ability of N1112OHDHP to act as phase promoter in aqueous solutions of non-ionic surfactants in comparison with other ionic liquids like N1112OHCl, N1112OHDHC or C2C1imC2SO4.

Prevention of Groundwater Pollution by Using the Electroosmotic Flushing of Soil Systems

Electrokinetic removal of hydrophobic organic compounds from soil systems of various compositions making it possible to avoid an ingress of toxicants into groundwater has been investigated. Solubilization of impurities was ensured by using aqueous solutions of nonionic surfactants belonging to the group of oxyethylated alkylphenols. The distribution curves of residual impurity content were obtained after the termination of electric treatment of soils following the passage of different volumes of electroosmotic solutions containing surfactants. The specified curves allow us to predict the possibility of achieving the required treatment efficiency.

Preparation of Mesoporous Molecular Sieve by the Reaction of Na 2 SiO 3 and H 2 SiF 6 in the Presence of an Aqueous Nonionic Surfactant Solution

Preparation of Mesoporous Molecular Sieve by the Reaction of Na 2 SiO 3 and H 2 SiF 6 in the Presence of an Aqueous Nonionic Surfactant Solution

Cloud point extraction of chlorophylls from spinach leaves using aqueous solutions of non-ionic surfactants.

Chlorophylls and their derivatives are currently used in a wide range of applications. To replace the volatile organic solvents commonly applied for their extraction from biomass, aqueous solutions of non-ionic surfactants are studied herein in the extraction of chlorophylls from spinach leaves. Aqueous solutions of several surfactants were screened, demonstrating that their hydrophilic-lipophilic balance (HLB) plays the pivotal role on the extraction performance, with the best results obtained for surfactants with a HLB ranging between 10 and 13. A response surface methodology (RSM) was then used to optimize operational conditions (surfactant concentration, solid-liquid ratio and temperature), leading to a maximum extraction yield of chlorophylls of 0.94 mg/g. After the extraction step, the chlorophylls-rich extract was concentrated by heating above the surfactant-water cloud point, leading to the separation into two-phases, and to a concentration factor of 9 and a recovery of 97% of chlorophylls in the surfactant-rich phase. The antioxidant activity of the extracts was finally appraised, showing that the antioxidant activity of the aqueous chlorophylls-rich extracts is higher than that obtained with volatile organic solvents. The obtained results show the potential of aqueous solutions of non-ionic surfactants to extract highly hydrophobic compounds from biomass and their possible direct use in cosmetic and nutraceutical applications, without requiring an additional recovery or purification step.

Mixed aqueous solutions of nonionic surfactants Brij 35/Triton X-100: Micellar properties, solutes' partitioning from micellar liquid chromatography and modelling with COSMOmic

Aqueous solutions of nonionic surfactants are of interest for bioprocesses, particularly as solubilizing agents for hydrophobic substances. To design such processes, the data on partition coefficients of solutes between micelles and their aqueous surrounding (Pmw) are of high value. An extended understanding of the partition behavior can be achieved from the structural information such as the micelle size and micelles composition.In this work, mixtures of nonionic surfactants Triton X-100 and Brij 35 were under study. The data on critical micelle concentrations showed partly non-ideal behavior of the solutions. The compositions of mixed micelles at different molar Brij 35/Triton X-100 ratios in the surfactant mixture were estimated from the data on self-diffusion coefficients (NMR diffusometry) and were calculated within the regular solution approach and predicted by Motomura’s model. The change of the mixed micelle composition in dependence on the total surfactant concentration was observed. It has been found, that the average value of the mixed micelles radii is ∼4nm. Whereas, the polydispersity indexes and the aggregation numbers increased with Triton X-100 fraction. Moreover, the Pmw values of different non-dissociated solutes (phenyl derivatives with various functional groups) were determined by means of micellar liquid chromatography (MLC) and were predicted using the thermodynamic model COSMOmic, an extension of COSMO-RS. In general, it has been proved that COSMOmic is able to predict Pmw in the mixed micellar system formed by nonionic surfactants.The obtained data show the possibility of modulating the partition behavior of solutes using the mixtures of nonionic surfactants. Apart from the hydrophobicity, the «surfactants – solute» specific interactions play an important role in the partition behavior of the investigated systems.

Thermodynamics of Micellization, Interfacial Behavior and Wettability Alteration of Aqueous Solution of Nonionic Surfactants

Abstract The present work deals with the physiochemical properties of polyoxyethylene sorbitan fatty acid esters (polysorbates), which are commonly known under the trade name Tween. Thermodynamics of micellization and adsorption at air-water interface for these nonionic surfactants solutions have been studied over a broad range of temperature. As the temperature of the surfactant solutions increases, the surface tension decreases whereas the critical micelle concentration (CMC) of each surfactant solution initially decreases and then increases. The free Gibb free energies of the micelle formation Δ G m o $\Delta {\rm{G}}_{\rm{m}}^{\rm{o}}$ , and the surfactant adsorption Δ G ads o $\Delta {\rm{G}}_{{\rm{ads}}}^{\rm{o}}$ , are calculated for the CMC of each surfactant at different temperatures. The surface or expanding pressure (Πcmc), minimum area per molecule (Amin), maximum surface excess (Γmax) are also calculated. The interfacial tension (IFT) between the aqueous surfactant solutions and the crude oil are measured at different concentrations of the surfactants using a spinning drop tensiometer. The contact angles are determined on an oil wet quartz surface to investigate the wettability alteration in the presence of Tween surfactants with varying salinity. FTIR analysis of quartz at dry and oil wet state, crude oil and COBRS (crude oil-brine-rock-surfactant) combinations are performed to identify the associated functional groups and their mutual interactions.

Effect of Some Vitamins of Group B (B1, B6, B12) on Micellar and Viscosity Properties of Anionic, Cationic and Nonionic Surfactants in Aqueous Solutions

Abstract The influence of vitamins B1 (thiamine hydrochloride), B6 (pyridoxine) and B12 (cyanocobalamine) on the micellization, surface activity and viscometric behavior of anionic surfactant sodium dodecylsulfate, cationic surfactant cetylpyridinium bromide and nonionic surfactant hexadecylpoly[oxyethylene(20)] alcohol at different temperatures was studied. The critical micelle concentration, the micellization thermodynamics, the maximum adsorption density, the standard free energy of adsorption and the other micellar parameters of surfactants in the presence of vitamins B1, B6 and B12 were obtained. On the basis of dependence of the relative viscosities on concentration, the viscosity B-coefficients of the Jones-Dole semiempirical equation were calculated for both premicellar and postmicellar regions. The results of our study allowed the conclusion that vitamins B1, B6 and B12 are solubilized in micelles.