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1.
Measurements of the surface tension of aqueous solution of mixtures of sodium dodecyl sulfate (SDDS) with methanol and ethanol
in SDDS concentration range from 10−5 to 10−2 M and mixtures of sodium hexadecyl sulfonate (SHS) with methanol and ethanol at SHS concentration from 10−5 to 8 × 10−4 M and for methanol and ethanol from 0 to 21.1 and, 11.97 M, respectively, were carried out at 293 K. Moreover, the surface
tension of aqueous solution mixtures of SDDS with propanol in the concentration range from 0 to 6.67 M taken from the literature
was also considered. The results obtained indicate that it is possible to describe the relationship between the surface tension
and molar concentration or molar fraction of alcohol by Szyszkowski and Connors equations. However, the Fainerman and Miller
equation allows us to predict the isotherm of the surfactant tension at constant anionic surfactants concentration at which
their molecules are present in the solution in the monomeric form if the molar area of surfactants and alcohols can be determined.
Based on the surface tension isotherms, the Gibbs surface excess of anionic surfactants and alcohols concentration at water–air
interface was determined and then recalculated for Guggenheim-Adam surface excess concentration of these substrates, and next
the molar fraction of alcohols and surfactants in the surface layer was determined. These molar fractions were discussed with
regard to surfactant and alcohol standard free energy of adsorption at the water–air interface determined from Langmuir and
Aronson and Rosen equations. The standard free energy of adsorption determined in these ways was compared to that deduced
on the basis of pC20 and Lifshitz van der Waals-components of the anionic surfactant and alcohol tails. 相似文献
2.
Effect of the Molecular Structure on the Adsorption Properties of Cationic Surfactants at the Air–Water Interface
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The surface activity and thermodynamic properties of adsorption at the air–water interface of two series of cationic surfactants based on isourea: the O-dodecyl-N,N′-diisopropylisourea hydrochloride, hydrobromide, and hydroiodide and the O-tridecafluorooctyl-N,N′-diisopropylisourea hydrochloride and hydrobromide were studied. The effect of structural parameters as the nature of the halide counter ion and the nature of the non-polar chain on the surface activity and thermodynamic properties of adsorption were investigated. The surface parameters, the maximum surface excess concentration (Γ max), the minimum area per molecule (A min) at the aqueous solution-air interface, effectiveness of surface tension reduction (πCMC), and efficiency of surface tension reduction (pC 20) were estimated. The standard Gibbs free energy of adsorption, (ΔG°ads) change has been calculated at different temperatures. 相似文献
3.
A Star-Shaped Anionic Surfactant: Synthesis,Alkalinity Resistance,Interfacial Tension and Emulsification Properties at the Crude Oil–Water Interface
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Rui Zhang Youfeng Cai Jixing Wang Zijing Zhao Xu Mao Zhigang Peng 《Journal of surfactants and detergents》2017,20(5):1027-1035
In this research, a star‐shaped surfactant was synthesized through the chlorination reaction, alkylation reaction and sulfonation reaction of triethanolamine, which is composed of three hydrophobic chains and three sulfonate hydrophilic groups. The critical micelle concentration (CMC) of the surfactant was measured by the surface tension method, and the results showed that it had high surface activity with CMC of 5.53 × 10?5 mol/L. The surfactant was superior in surface active properties to the reference surfactants SDBS and DADS‐C12. The interfacial tension (IFT) of the studied crude oil–water system (surfactant concentration 0.1 g/L, NaOH concentration 0.5 g/L, and experimental temperature 50 °C) dropped to 1.1 × 10?4 mN/m, which can fulfil the requirement of surfactants for oil displacement. An aqueous solution of the surfactant and crude oil was emulsified by shaking, which formed a highly stable oil‐in‐water (O/W) emulsion with particle size of 5–20 μm. The oil displacement effect was almost 12%. 相似文献
4.
Measurements of the surface tension (γ
LV
) and the advancing contact angle (θ) on poly(tetrafluoroethylene) (PTFE) were carried out for aqueous solutions of sodium decyl sulfate (SDS) and sodium dodecyl
sulfate (SDDS) and their mixtures. The results obtained indicate that the values of the surface tension and the contact angle
of solutions of surfactants on PTFE surface depend on the concentration and composition of the surfactants mixture. On the
curves presenting the relationship between the surface tension, contact angle and monomer mole fraction of SDDS (α) in the mixture of SDDS and SDS, there is a minimum at α equal to 0.8 which together with the negative values of the interaction parameters indicate that synergism occurs in surface
tension and contact angle reduction almost in the range of concentration corresponding to the saturated monolayer of surfactants
at the water–air interface. The results and calculations obtained also indicate that for single surfactants and their mixtures
at a given concentration in the bulk phase, the values of surface excess concentration of the surfactants at water–air and
PTFE–water interfaces are nearly the same, which suggests that the orientation of SDDS and SDS molecules at both interfaces
in saturated monolayer should be vertical to the interfaces. Taking into account the values of the monomer mole fractions
of the surfactants in a mixed monolayer at the water–air interface and values of the contact angle of a single surfactant
on the PTFE surface, it is possible in a simple way to predict the values of the contact angle of a mixture at a given concentration
and composition. 相似文献
5.
Ramon E. Vera Franklin Salazar-Rodríguez Ronald Marquez Ana M. Forgiarini 《Journal of surfactants and detergents》2020,23(3):603-615
In this work, we present the effects of salts on sodium dodecyl benzene sulfonate micellization and on the interfacial performance of a sodium dodecyl benzene sulfonate–heptane–brine system at optimum formulation, i.e., hydrophilic–lipophilic deviation (HLD) = 0. In order to do that, interfacial tension and dilational interfacial rheology properties of surfactant–heptane–water systems at optimum formulation are measured using an interfacial spinning drop tensiometer with an oscillating velocity, which can accurately measure interfacial rheology properties at both low and ultralow interfacial tensions. The brines used contain one of the following salts: MgCl2, CaCl2, NaCl, NH4Cl, NaNO3, CH3COONa, or Na2SO4. We performed a one-dimensional salinity scan with each of these salts to achieve an optimum formulation. In relation to the Hofmeister series, we found that, at optimum formulation, systems with chaotropic ions (NH4+, NO3−) present interfaces with ultralow interfacial tensions, very low dilational modulus, and a low phase angle, whereas kosmotropic ions (Mg2+, Ca2+, SO4−2) generate high interfacial tension and high rigidity monolayers. Intermediate ions in the Hofmeister series (Na+, CH3COO−, Cl−) present interfaces with intermediate properties. Furthermore, according to the Hofmeister series, interfaces can be respectively ordered from higher to lower rigidity for surfactant counterions Mg2+ > Ca2+ > Na+ > NH4+ and coions SO42− > CH3COO– > Cl− > NO3−, which correspond to a salting-out (highest rigidity) and salting-in (lowest rigidity) effect. We observed that counterions have a more significant effect on surfactant–oil–water system properties than those that act as coions. 相似文献
6.
Mixed Micellization of Polyoxyethylene (20) Oleyl Ether with Cetylpyridinium Chloride at the Air–Water Interface
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Adsorption and micellization behaviour of binary surfactant mixtures containing a nonionic surfactant, polyoxyethylene (20) oleyl ether (C18-1E20), and a cationic surfactant, cetylpyridinium chloride (CPC), was studied at the air–water interface using the Wilhelmy plate method. A pseudo-phase separation model was used to analyse mixed micellization. A Margules equation with one constant (interaction parameter, β) was fitted to the nonideal behaviour of the mixed surfactant system. This system shows synergism (β = ?6.0) for micellization. The dynamic behaviour and foamability of binary mixtures at the same bulk concentration and at different mole fractions were also studied using drop volume and horizontal impinging jet methods, respectively. It was found that with an increase in the mole fraction of C18-1E20, the foamability of a mixture increases and t* value decreases. 相似文献
7.
Dalia Emam Mohamed Nabel A. Negm Marwa R. Mishrif 《Journal of surfactants and detergents》2013,16(5):723-731
The interfacial and micellization behaviors of binary mixtures of two gemini cationic surfactants and conventional the cetyl trimethyl ammonium bromide surfactant were studied at various molar ratios. From the equilibrium surface tension measurements, the critical micelle concentrations (CMC) data were obtained as functions of the composition. Values of the CMC were analyzed according to the regular solution model developed by Rubingh for mixed micelles. Two interaction parameters were obtained for each system, the interaction at the interface, and in the micellar phase. The results showed that micellization and adsorption properties of the studied mixed systems depend on the spacer chain lengths of the gemini surfactants and their ratio in the mixed systems. 相似文献
8.
Ronald Marquez Luz Meza José G. Alvarado Johnny Bullón Dominique Langevin Ana M. Forgiarini Jean-Louis Salager 《Journal of surfactants and detergents》2021,24(6):587-601
Three different cases were selected to study the effect of physicochemical formulation on interfacial rheology properties of surfactant–oil–water (SOW) systems by increasing the complexity of the system from a basic case. This was performed by changing the normalized hydrophilic–lipophilic deviation (HLDN) to attain the optimum formulation at HLDN = 0. Two types of SOW systems were studied: the first one used an ionic surfactant with a salinity scan, and the second one a mixture of two nonionic surfactants in a formulation scan produced by changing their proportion. Both of them contained cyclohexane as a pure oil phase, without alcohol. Sec-butanol was then added as a co-surfactant with hardly any formulation influence on HLDN. The complexity in interfacial rheology was then increased by changing the oil to a light crude with low asphaltene content. The interfacial rheology is also reported for a realistic system with a high asphaltene content comprised of crude oil diluted in cyclohexane with a conventional surfactant and a commercial demulsifier. The findings confirm that at optimum formulation and whatever the scanning variable (salinity, average ethylene oxide number in the nonionic surfactant mixture, or surfactant/demulsifier concentration), the interfacial tension, and interfacial elastic moduli E, E′, and E″ exhibit a deep minimum. These observations are related to the acceleration of the surfactant exchanges between the interface, oil, and water, near the optimum formulation. Several arguments are put forward to explain how these findings could contribute to the decrease in emulsion stability at HLDN = 0. 相似文献
9.
Ronald Marquez Raquel Antón Francia Vejar Jean-Louis Salager Ana M. Forgiarini 《Journal of surfactants and detergents》2019,22(2):177-188
This article is a continuation of our first study on dilational interfacial rheology properties at optimum formulation for surfactant-oil–water systems at low surfactant concentration just above the cμc. Here, we have investigated a high content of middle-phase microemulsion with an optimum WIII phase behavior for a system containing sodium dodecyl sulfate, n-pentanol, and kerosene. A new oscillating spinning drop interfacial rheometer was used to measure the interfacial properties. The very low dilational elasticity moduli and phase angle found at or near hydrophilic–lipophilic deviation (HLD) = 0 are related to the presence of the bicontinuous phase microemulsion and to the fast surfactant exchanges between the bulk and the interface, regardless of the phases involved in the measurement using the spinning drop apparatus, i.e., the two-phase excess oil and excess water (O-W) or the bicontinuous microemulsion and excess water (M-W). We show that at or near optimum formulation, the interfacial tension and the dilational modulus for the M-W case almost instantly reach equilibrium, because of the high surfactant content in the microemulsion and the fast exchanges between the bulk and the interface. In contrast, when both excess phases (O-W) are measured, the changes in these properties are slower, due to the scarce presence of surfactants in both phases. The possibility of having almost all the surfactants trapped in the middle-phase bicontinuous microemulsion could explain the emulsion instability in all the WIII range. This is behaving as if there were no surfactant available in the oil and water phases to stabilize the oil or water droplets thus formed. 相似文献
10.
The aqueous mixed systems (EO76PO30EO76) (TBCP8400)—cetyltrimethyl ammonium tosylate (CTAT), and (EO97PO69EO97) (TBCP12600)—CTAT were studied to determine both the bulk aggregation and the adsorbed monolayer at the air/water interface.
Results were interpreted with the pseudophase separation model plus the regular solution theory for aggregates and monolayers.
The behavior is different for TBCP8400–CTAT and TBCP12600–CTAT mixtures, but it is strongly non-ideal in both cases. In bulk,
TBCP8400–CTAT mixtures produce aggregates more close to CTAT micelles having TBCP8400 as a solubilizate than the inverse.
At low CTAT content, the interaction is repulsive becoming attractive at high TBCP8400 content. The TBCP12600–CTAT aggregates
strongly differ from the structure of both pure component micelles, and the interaction is always repulsive. In both cases,
the interaction seems not to be cooperative but gradual. CTAT effect on copolymers aggregates seems to be more similar to
that of a zwitterionic surfactant than to that of an ionic one. However, CTAT is not included in the aggregates as an ion
pair, as revealed by the ionization degree results. It seems that cetyltrimethyl ammonium and tosylate ions have different
effects on aggregates which in part are opposite. The adsorbed monolayers also show different behavior. In TBCP8400–CTAT system,
the monolayer is mainly a CTAT one with inclusion of TBCP8400 as a monolayer-soluble impurity. However, the inclusion of the
non-ionic surfactant alters the structure of the monolayer, which differs from that of the pure CTAT one. The area per adsorbed
molecule (A0) is systematically higher than the ideal and computed ones. The system TBCP12600–CTAT shows a monolayer composition which
is almost the same that the overall surfactant mixture composition, and the monolayer structure differs from both the pure-TBCP12600
and the pure-CTAT monolayers ones. The experimental A0 values are systematically lower than the ideal and the computed ones. Then, in both cases the A0 values for the pure components do not remain invariable in the mixed monolayer. The phenomenon is interpreted on the basis
of the conformation of the copolymers adsorbed at the air/solution interface. 相似文献
11.
Adsorption Behavior of Trimethylolpropane-Dehydroabietic Acid Ester at the Air–water Interface
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Juying Zhou Yanping Yang Yuyan Liang Fuhou Lei Haitang Xu Jianfang Lu Yanzhi Zhao Yan Zhou 《Journal of surfactants and detergents》2016,19(6):1143-1151
A novel amphipathic trimethylolpropane-dehydroabietic acid ester was successfully prepared with acyl chloride method. Various analytical techniques such as liquid chromatography–mass spectrometry, Fourier transform infrared spectrometry, proton and carbon nuclear magnetic resonance spectroscopy were employed to evaluate the chemical structure of the ester. The surface properties of the ester were investigated by surface tension and resonance light-scattering techniques. The surfactant molecules are adsorbed at the water–air interface in different adsorption states, i.e., state 1 and 2. The dynamic adsorption behavior was studied by combining experimental results and a reorientation model. The molar fraction of solvent decreased, while the molar fraction of surfactant molecules increased with increasing ester concentration at the surface layer. The adsorption value of state 1 presented a unimodal shape and the adsorption value of state 2 presented an s-shape with the increase in surface pressure. The free energy of adsorption is ?36.06 kJ mol?1, more negative than the free energy of micellization (?29.69 kJ mol?1), it is actually easier for surfactant molecules to adsorb on the air–water interface. 相似文献
12.
S. P. Medvedev B. E. Gel'fand A. N. Polenov S. V. Khomik 《Combustion, Explosion, and Shock Waves》2002,38(4):381-386
Combustion of fog consisting of a hydrogen–air mixture, water vapor, and ultrafine particles of water is studied experimentally. Inflammable fog was generated by sudden expansion of a system hydrogenair + water vapor. It is shown that partial condensation of vapor with the formation of microdroplets constricts the flammability limits. Key words: flammability limits, heterogeneous mixtures, rarefaction wave, IR diagnostics. 相似文献
13.
Mohamed Aoudia Zuleihka Al-Harthi Rashid S. Al-Maamari Christie Lee Paul Berger 《Journal of surfactants and detergents》2010,13(3):233-242
The effect of surfactant concentration on the occurrence and detection of transient ultralow interfacial tension (IFT) between
crude oil and formation water at 75 °C has been investigated using a series of novel sodium alkyl ether sulfonates having
various increasing molecular weights and degrees of ethoxylation. All surfactant systems displayed dynamic interfacial tension
(DIT). Transient ultralow DIT (DITmin) were detected only within an intermediate surfactant concentration. This behavior was attributed to an implicit concentration-related
length scale required for the added surfactant to diffuse from the bulk phase to the freshly prepared oil–water interface.
In the high surfactant concentration range, this length scale is relatively short and results in an instantaneous (and undetectable)
occurrence of DITmim in a relatively very short time scale, well beyond the detection limit of the spinning drop tensiometer (~2–3 min). Interestingly,
DITmin were detected only in systems above the surfactant’s critical micelle concentration, suggesting that DITmin occurs as a result of the diffusion (subsequent to the adsorption) of the oil acidic species from the interface to the bulk
phase to form mixed micelles with the added surfactant. Measurements of DITs in the presence of decane showed no evidence
for DITmin, confirming the general belief that DITmin is indeed due to the interaction of the added surfactant with the oil acidic components. Finally, the effect of surfactant
concentration on the equilibrium IFT (γeq) showed evidence for relatively low values (~10−2 mNm−1) for some surfactant systems. 相似文献
14.
Caroline Rondel Isabelle Alric Zéphirin Mouloungui Jean-François Blanco Françoise Silvestre 《Journal of surfactants and detergents》2009,12(3):269-275
The acylation of amino acids by acid chlorides with from 8 to 12 carbon atoms in alkaline aqueous medium following Schotten–Baumann reaction results in sodium salts of a N α-acylamino acid and fatty acid mixture. The latter are present in a proportion from 40 to 60%. These compositions represent mixtures of amphiphilic anionic surfactants. Together they contribute to the properties of the formulation. Measurements of the surface-active properties of these formulations, such as critical micelle concentration (CMC), surface tension at the CMC (ST), foaming capacity (FC) and foaming stability (FS), show that surfactant mixtures with the longest chain have the most desirable properties. They are comparable to commercial petroleum-based surfactants. Thus, the CMC, ST and CM values of the formulation obtained starting from leucine and dodecanoyl chloride (310 mg/l, 30.1 mN/m and 200%, respectively) are similar to, and even better than, sodium dodecylsulfate (290 mg/l, 39.1 mN/m and 230%, respectively). 相似文献
15.
Effect of Narrow Oxirane Adduct Distribution on the Adsorption of Disodium Alcohol Ethoxylates Sulfosuccinate at Air–Aqueous Solution Interface
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Adsorption behaviors at the air–water interface were presented for disodium alcohol ethoxylate sulfosuccinates (AESS) with narrow and broad oxirane adduct distribution. The CMC and equilibrium surface tension γeq of broad‐range distributed (BRD) and narrow‐range distributed (NRD) AESS2 (with average degrees of ethoxylation of 2) were measured by the Wilhelmy plate method, while the adsorption and thermodynamic parameters were calculated. The effect of temperature and inorganic electrolyte on adsorption behaviors of these two surfactants was also investigated. The results show that NRD AESS2 displays a lower CMC and higher γeq compared with BRD AESS2. At the same time, the maximum surface excess concentration Γmax of NRD AESS2 was lower than that of BRD AESS2 because of its larger steric hindrance, leading to the different adsorption and thermodynamic parameters. The adsorption of NRD AESS2 and BRD AESS2 was weakened with increasing temperature and enhanced in the presence of inorganic electrolyte. 相似文献
16.
S. O. Yeboah I. Oathotse W. A. A. Ddamba 《Journal of the American Oil Chemists' Society》2014,91(6):1065-1075
Densities ρ, ultrasonic speeds u and dynamic viscosities η, of mixtures of morama, Tylosema esculentum, seed oil with n‐hexane, n‐heptane, n‐octane and n‐nonane were determined over the entire composition range at 298.15 K and atmospheric pressure. Excess molar volumes, , excess molar free volumes , deviations in isentropic compressibility, Δκs, deviations in ultrasonic speed, Δu, deviations in viscosity, Δη, and the excess free energy of activation of viscous flow, ΔG*E, were calculated therefrom and correlated by the Redlich–Kister equation for each of the [morama seed oil + (n‐hexane or n‐heptane or n‐octane or n‐nonane)] mixtures. The results have been discussed in terms of possible intermolecular interactions and structural effects. 相似文献
17.
Morten M. Smedskjaer Yuanzheng Yue 《International Journal of Applied Glass Science》2011,2(2):117-128
In this paper, we review our recent findings about both the cationic inward and outward diffusion processes in glasses and glass–ceramics caused by redox reactions. We provide new insights into these findings by mapping the diffusion depth, the thermal reduction temperature, and time in a three dimensional diagram and by looking into the correlation among the glass composition, structure, topology, and the diffusion process in the polyvalent elements containing glasses. We illustrate the link between glassy dynamics (via the liquid fragility index m) and activation energy of diffusion. Furthermore, the inward diffusion approach is used to study percolation phenomena in glass–ceramics. Finally, we show that the diffusion approaches are potential tools for tailoring the surface performances of bulk glasses and glass fibers. 相似文献
18.
V. Sh. Shagapov A. S. Chiglintseva G. R. Rafikova 《Theoretical Foundations of Chemical Engineering》2018,52(4):560-567
The problem of methane hydrate formation when the process is controlled by gas diffusion in the hydrate layer formed at the gas–ice (or water) interface is solved. It is shown that an approximate quasi-stationary solution of the diffusion equation is in good agreement with its numerical solution over a wide range of the solubility of the gas in the hydrate, which is dependent on pressure. It is found that the time for the complete transition of the water (or ice) phase into the hydrate state decreases with an increase in the saturation concentration of the mobile gas in the hydrate. The kinetic equations derived based on a quasi-stationary solution of the diffusion equation, which are relationships for the intensity of hydrate formation in snow-containing (or water-containing) formations during the filtration of hydrate-forming gases, are used to describe the concentration fields of the diffusing gas and the dynamics of hydrate layer growth. 相似文献
19.
A support vector machine (SVM) model is presented concerning accurate prediction of the surface tension of the complex mixtures of ionic liquids (ILs)–amines–water using the most important types of amines employed in the gas sweetening plants, such as monoethanolamine, diethanolamine, and methyldiethanolamine. Different ILs, such as [bmim] [BF4], [bmim] [DCA], [mmim] [dmp], [emim] [dep], [bmim] [BF4], [bmim] [Br], [bmim] [BF4], and [bmim] [Br], are considered in the presented model. The effects of most important influencing parameters, such as temperature and mass fraction of amines and ILs, on the surface tension of the aqueous mixtures of ILs and amines are well represented. A comparison of the presented model and the most important models reveals that the suggested SVM model has better performance in terms of accuracy and generalizability. The percentage average absolute deviation between the predicted and experimental surface tensions is about 0.44% suggesting the superiority of the presented model over wide ranges of temperatures and species concentrations. 相似文献
20.
Matteo Lualdi Sara Lögdberg Francesco Regali Magali Boutonnet Sven Järås 《Topics in Catalysis》2011,54(13-15):977-985
A series of different mechanical mixtures of a narrow-pore Co/γ-Al2O3 catalyst and a Cu-based WGS-catalyst has been investigated in the low-temperature Fischer–Tropsch synthesis (483 K, 20 bar) with a model bio-syngas (H2/CO = 1.0) in a fixed-bed reactor. The higher the fraction of WGS-catalyst in the mixture, the lower is the Co-catalyst-time yield to hydrocarbons. This is ascribed to a strong positive kinetic effect of water on the Fischer–Tropsch rate of the Co-catalyst, showing the importance of the indigenously produced water, especially in fixed-bed reactors where the partial pressure of water is zero at the reactor inlet. A preliminary kinetic modeling suggests that the reaction order in P $ _{{{\text{H}}_{ 2} {\text{O}}}} $ is 0.3 for the Co/γ-Al2O3 catalyst in the range of the studied reactor-average partial pressures of water (i.e., 0.04–1.2 bar). 相似文献