Surface Tension Of Mixture Research Articles

Ethylene Glycol and Its Mixtures with Water and Electrolytes: Thermodynamic and Transport Properties

A comprehensive thermodynamic model has been developed for calculating thermodynamic and transport properties of mixtures containing monoethylene glycol (MEG), water, and inorganic salts and gases. The model is based on the previously developed mixed-solvent electrolyte (MSE) framework, which has been designed for the simultaneous calculation of phase equilibria and speciation of electrolytes in aqueous, nonaqueous, and mixed solvents up to the saturation or pure solute limit. In the MSE framework, the standard-state properties of species are calculated from the Helgeson–Kirkham–Flowers equation of state, whereas the excess Gibbs energy includes a long-range electrostatic interaction term expressed by a Pitzer–Debye–Hückel equation, a virial coefficient-type term for interactions between ions and a short-range term for interactions involving neutral molecules. Model parameters have been established to reproduce the vapor pressures, solubilities of solids and gases, heat capacities, and densities for MEG + H2O + solute systems, where the solute is one or more of the following components: NaCl, KCl, CaCl2, Na2SO4, K2SO4, CaSO4, BaSO4, Na2CO3, K2CO3, NaHCO3, KHCO3, CaCO3, HCl, CO2, H2S, and O2. In particular, emphasis has been put on accurately representing the solubilities of mineral scales, which commonly appear in oil and gas environments. Additionally, the model predicts the pH of mixed-solvent solutions up to high MEG contents. On the basis of speciation obtained from the thermodynamic model, the electrical conductivity of the MEG + H2O + NaCl + NaHCO3 solutions is also calculated over wide ranges of solvent composition and salt concentration. Additionally, associated models have been established to compute the thermal conductivity, viscosity, and surface tension of aqueous MEG mixtures.

Prediction of the Surface Tension, Surface Concentration and the Relative Gibbs Adsorption Isotherm of Non-ideal Binary Liquid Mixtures

Surface properties of binary mixtures of 1,2-ethanediol, 1,2-propanediol and 1,4-butanediol with acetonitrile have been measured by the surface tension method at T = 298.15 K and atmospheric pressure. The surface tension has been predicted based on the Suarez method. This method combines a model for the description of surface tension of liquid mixtures by using the UNIFAC group contribution method for calculation of activity coefficients. Also, the results have been discussed in terms of surface concentration and lyophobicity using the extended Langmuir isotherm. The results provide information on the molecular interactions between the unlike molecules that exist at the surface and the bulk phase. Finally, experimental values of the surface tension have been correlated by the Redlich–Kister and Wang–Chen polynomial equations over the whole mole fraction range.

New Method to Predict the Surface Tension of Complex Synthetic and Biological Polyelectrolyte/Surfactant Mixtures

Although the surface tension of complex mixtures determines the fate of many important natural processes, the property is notoriously difficult to interpret. Here we announce a new method that successfully predicts the surface tension of two synthetic and one biological polyelectrolyte/surfactant mixtures in the phase-separation region after dynamic changes in the bulk phase behavior have reached completion. The approach is based on the nonequilibrium framework of a lack of colloidal stability of bulk complexes in compositions around the charge match point of the oppositely charged components and requires as input parameters only the surface tension isotherm of the pure surfactant and some bulk measurements of the mixtures; no surface measurements of the mixtures are required. The complexity of the problem is reduced to a single empirical equation. This simplification in our understanding of the surface properties of strongly interacting mixtures involving macromolecules can lead to the optimization of applications involving synthetic polymers and biomacromolecules such as DNA at surfaces.

Thermophysical Properties of Binary Liquid Systems of Ethanoic Acid, Propanoic Acid, and Butanoic Acid with Benzene or Acetophenone

The density (), viscosity (), and surface tension () of binary mixtures of carboxylic acids (CAs) (ethanoic acid (EA), propanoic acid (PA), butanoic acid (BA)) + benzene (BEN) or acetophenone (ACT) have been measured at 298.15, 308.15, and 318.15 K. From the experimental results, excess values of molar volume (), viscosity (), Gibb's free energy for the activation of low (), and surface tension () were evaluated and fitted to a Redlich-Kister type of equation. The parameter “” of Grunberg and Nissan expression has also been calculated. From the sign and magnitude of , , , , and “” values, it is concluded that specific interactions are present in CA+ACT system and these interactions are absent in CA + BEN mixtures. Various viscosity and surface tension models have been used to test the consistency of the data.

Estimation of Surface Tension of Ionic Liquid–Cosolvent Binary Mixtures by a Modified Hildebrand–Scott Equation

The correlation model of gas–liquid interfacial tension (surface tension) of nonaqueous mixtures containing ionic liquids (ILs) is still in its infancy. The purpose of this work is to develop a modified Hildebrand–Scott equation based on local composition concept and the group surface area parameters of UNIFAC model as well as to evaluate the capability of this model. The surface tension of 33 IL–cosolvent binary systems were correlated by the modified Hildebrand–Scott equation with two energy parameters and an overall average relative deviation of only 0.92%. The ILs in the study included imidazolium-based, pyridinium-based, and isoquinolinium-based ones, and the cosolvents included methanol, ethanol, 1-propanol, 1-butanol, 1-pentanol, acetonitrile, and tetrahydrofuran. Using the energy parameters obtained from the surface tension of a given IL–cosolvent binary system at 298.15 K, the surface tension of the same system at other different temperatures was predicted by the modified Hildebrand–Scott equation, with an overall average relative deviation of 1.06%.

Effect of temperature and composition on the density, viscosity surface tension and excess quantities of binary mixtures of 1-ethyl-3-methylimidazolium tricyanomethanide with thiophene

Thermal properties of the ionic liquid (IL) 1-ethyl-3-methylimidazolium tricyanomethanide, ([EMIM][TCM]), measured by the Differential scanning calorimetry (DSC) as glass transition temperature (Tg,1), heat capacity change at glass transition temperature (ΔCp(g),1), melting temperature (Tfus), enthalpy of melting (ΔHfus), phase transition temperature (Ttr), enthalpy of phase transition (ΔtrH) and decomposition temperature (Td) were presented. The density and viscosity for the binary mixtures containing [EMIM][TCM] and thiophene at six temperatures (298.15, 308.15, 318.15, 328.15, 338.15 and 348.15K) and ambient pressure were reported. The density and viscosity as a function of temperature were tested by an empirical second-order polynomial and by the Vogel–Fucher–Tammann equation. The density and viscosity variations with compositions were described by polynomials. Excess molar volumes were described by the Redlich–Kister polynomial expansion. Viscosity deviations were calculated and correlated by the Redlich–Kister polynomial expansions. The surface tensions of pure ionic liquid and binary mixtures of [EMIM][TCM] and thiophene were measured at atmospheric pressure at five temperatures (298.15, 308.15, 318.15, 328.15, and 338.15K). The surface tension deviations were calculated and correlated by the Redlich–Kister polynomial expansion. The temperature dependence of interfacial tension was used to evaluate the excess surface energy, the surface enthalpy, the critical temperature, parachor and speed of sound for pure ionic liquid. These measurements have been provided to complete information of the influence of temperature on physico-chemical properties for the selected IL, which was chosen as a possible new entrainer in the separation of sulfur compounds from fuels. A qualitative analysis on these quantities in terms of molecular interactions is reported. The obtained results indicate that ionic liquid interactions with alcohols are strong dependent on the special trend of packing effects and hydrogen bonding of this ionic liquid with polar solvent.

An adaptive finite element method for simulating surface tension with the gradient theory of fluid interfaces

The gradient theory for the surface tension of simple fluids and mixtures is rigorously analyzed based on mathematical theory. The finite element approximation of surface tension is developed and analyzed, and moreover, an adaptive finite element method based on a physical-based estimator is proposed and it can be coupled efficiently with Newton’s method as well. The numerical tests are carried out both to verify the proposed theory and to demonstrate the efficiency of the proposed method.

Surface tension of solutions containing dicarboxylic acids with ammonium sulfate, d-glucose, or humic acid

To examine the effect of organic/inorganic solutes on the properties of cloud condensation nuclei and other atmospheric aerosols, the surface tension of various mixtures including dicarboxylic acids, ammonium sulfate, d-glucose, and humic acid sodium salt (NaHA) was measured at 20°C using the Wilhelmy plate method. An equimolar mixture of oxalic/malonic acids (0–0.5mol/kg water) was added to ammonium sulfate (0.1–3mol/kg water), d-glucose (0.01–2mol/kg water), and NaHA (0.1–10g/kg water) solutions. The surface tensions of ammonium sulfate, d-glucose, and NaHA solutions decreased as the concentration of the added oxalic/malonic acid mixture increased. The trend in surface tension for the ammonium sulfate solution is roughly similar with and without the addition of the oxalic/malonic acid mixture. However, the surface tension trend for the d-glucose and NaHA solutions with the oxalic/malonic acid mixtures does not follow that of pure d-glucose and NaHA solutions. With the presence of oxalic/malonic acids in the solution, the surface tension increase by d-glucose becomes larger and the surface tension reduction by NaHA becomes smaller.

Physical Properties of Binary Liquid Systems: Ethanoic Acid/Propanoic Acid/Butanoic Acid with Cresols

Density, viscosity and surface tension of nine binary liquid systems: ethanoic acid, propanoic acid and butanoic acid with o-cresol, m-cresol and p-cresol have been determined at 298.15, 308.15 and 318.15 K over the complete compositional range. From the experimental results the excess values of molar volume (V E), viscosity (η E), Gibbs free energy for the activation of flow (ΔG E) and surface tension (σ E) were evaluated. The excess values were fitted to the Redlich–Kister type equation using a nonlinear regression technique. The Grunberg–Nissan parameter, d, was also calculated. From the sign and magnitude of the V E, η E, ΔG E, σ E, and d values, it is concluded that specific interactions are present in all of the nine binary mixtures under study. V E is negative for carboxylic acid–cresol mixtures at all temperatures and over the entire composition range. The values of η E, ΔG E and σ E are positive over the whole range of composition and increase with increasing temperature at a constant mole fraction of the carboxylic acid, confirming the existence of specific interactions in these binary mixtures. Further, the viscosity data of the binary systems were fitted to various theoretical/empirical models. The binary viscosity data is well represented by the Auslander model. Surface tension data were fitted to various theoretical/empirical models. The binary mixture surface tension data are well represented by the model given by Zihao and Jufu.

Modeling the surface tension of refrigerant mixtures with linear gradient theory

In this work, the surface tensions of pure refrigerants and binary, ternary, and quaternary refrigerant mixtures were modeled. A simple and reliable model was used, combining the linear gradient theory (LGT) with the Heyen equation of state (Heyen EOS), to take advantage of the well described equilibrium densities of phases and surface tensions of refrigerant mixtures. The binary interaction parameters of the Heyen EOS were determined to improve the description of the equilibrium properties of bulk phases. A new correlation for the influence parameter is also proposed that is a function of the densities of the bulk phases. The geometric mixing rule for the mixture influence parameter is also selected without adjustable coefficients, making this model predictive. The surface tensions predicted by the model agree well with experimental data for pure refrigerants and binary, ternary, and quaternary refrigerant mixtures (overall AAD∼3.27%).

An analytical and experimental study of heat pipe performance with a working fluid exhibiting strong concentration Marangoni effects

An original performance study of an inclined gravity-assisted heat pipe with a 0.05M 2-propanol/water binary mixture, exhibiting strong concentration Marangoni effects, was experimentally investigated. Initial experiments were carried out for varying liquid charge levels between 30% and 70%, to determine an optimal value that would enhance heat transport performance by maximizing the critical heat flux (CHF) condition, while reducing the evaporator wall superheat. A 45% liquid charge ratio was found to have the lowest overall superheat, and highest CHF condition attained, as high as 114.8W/cm2. Nucleate pool boiling contributions were found to have a greater impact on heat pipe thermal conductance, constituting 65% and 71% of the total heat transport for water and 0.05M 2-propanol/water mixture respectively. Additionally, a 49% thermal conductance and 53% CHF improvement was found with 0.05M 2-propanol/water as the working fluid over that of pure water. This investigation also introduces a novel binary mixture model for the inclined, gravity-assisted heat pipe. Modeling results of the system with a 45% fill ratio were found to provide good prediction of the experimental results with an average thermal conductance deviation of 0.5W/K, and an evaporator-section pool boiling rms deviation of 14.3%. This model employs an average pseudo single-component (PSC) coefficient in place of an ideal heat transfer coefficient (HTC), and an empirically-determined binary mixture surface tension correlation, due to the non-ideal nature of the low concentration 2-propanol/water mixture.

Surface tensions of binary mixtures of ionic liquids with bis(trifluoromethylsulfonyl)imide as the common anion

While values for thermophysical properties of ionic liquids are becoming widely available, data for ionic liquid mixtures are still scarce. In an effort to overcome this limitation and understand the behavior of ionic liquid mixtures, novel data for the surface tension of mixtures composed of 1-butyl-3-methylimidazolium bis(trifluoromethylsulfonyl)imide, [C4mim][NTf2], with other ionic liquids with a common anion, namely 1-butyl-2,3-dimethylimidazolium, [C4C1mim]+, 3-methyl-1-propylpyridinium, [C3mpy]+, 1-methyl-1-propylpyrrolidinium, [C3mpyr]+, and 1-methyl-1-propylpiperidinium, [C3mpip]+, were measured at T=298.2K and atmospheric pressure over the entire composition range. From the surface tension deviations derived from the experimental results, it was possible to infer that the cation alkyl chain length of the second ionic liquid constituting the mixture has a stronger influence in the ideal mixture behavior than the type of family the ionic liquid cation belongs to. The Gibbs adsorption isotherms, estimated from the experimental values, show that the composition of the vapor–liquid interface is not the same as that of the bulk and that the interface is richer in the ionic liquid with the lowest surface tension, [C4mim][NTf2].

Prediction of surface tension and surface properties of organic binary mixtures

The Sprow–Prausnitz equation is employed to describe quantitatively the nature, properties and compositions of surface layers in binary liquid mixtures. Wide variety application, high accuracy, and required parameters that are normally easy to obtain are advantages of Sprow–Prausnitz equation compared to other methods.Bulk mole fraction, surface molar area and surface tension of pure component are necessary inputs for this equation. UNIFAC group contribution method is also applied into account for the non-ideality of the bulk liquid as well as that of the surface layer. The average relative error obtained from the comparison of experimental and calculated surface tension values for 154 binary systems with different surface tension behaviors show the model has good accuracy in comparison with other predictive equations. In addition to find more information about surface structure of binary mixtures, surface tension of binary mixtures has been studied using extended Langmuir model (EL).

Study of surface tension and surface properties of binary systems of DMSO with long chain alcohols at various temperatures

Surface tensions of binary mixtures of DMSO (dimethyl sulphoxide) with a series of long chain aliphatic alcohols (1-propanol, 1-butanol, and 1-hexanol) were measured as a function of composition using the ring detachment method in the temperature range between (288.15 and 328.15)K. The surface tension results are used to describe quantitatively the nature, properties, and compositions of surface layers in binary liquid mixtures. The temperature influence on the behaviour of surface tensions and surface properties of binary mixtures has often been used to obtain information about solute structural effects on DMSO. The surface tension of the above mentioned binary systems were correlated with empirical and thermodynamic based models. The average relative error obtained from the comparison of experimental and calculated surface tension values for 15 binary systems with three models is less than 1%. In addition to finding more information about the surface structure of binary mixtures, surface mole fraction was calculated using an extended Langmuir model (EL). The temperature dependence of σ at fixed composition of solutions was used to estimate surface enthalpy, Hs, and surface entropy, Ss. The results provide information on the molecular interactions between the unlike molecules that exist at the surface and the bulk.

Density, Viscosity, Speed of Sound, Surface Tension, and Flash Point of Binary Mixtures of n-Hexadecane and 2,2,4,4,6,8,8-Heptamethylnonane and of Algal-Based Hydrotreated Renewable Diesel

The physical properties of algal hydrotreated renewal diesel (algal HRD) and several binary mixtures of n-hexadecane and 2,2,4,4,6,8,8-heptamethylnonane were measured in this work. The density and viscosity were measured at temperatures ranging from (293.15 to 393.15) K and the pure components values fell within the range of previously reported values. Speed of sound data were measured at temperatures ranging from (293.15 to 323.15) K and ranged from (1170 to 1360) m·s–1. The bulk modulus was calculated from the density and speed of sound data, and its values ranged from (1050 to 1425) MPa. For the pure n-hexadecane and 2,2,4,4,6,8,8-heptamethylnonane and their mixtures, the flash point values ranged from (367 to 408) K and the surface tension values ranged from (24.1 to 27.3) mN·m–1. The values of viscosity and flash point (360 K) for the algal HRD did not fall within the range of values for the mixtures of n-hexadecane and 2,2,4,4,6,8,8-heptamethylnonane, but the values of density, speed of sound, bulk ...

Critical evaluation of surface tension of binary liquid mixtures from associated and nonassociated processes at various temperatures: an experimental and theoretical study

Densities and surface tensions were measured for the binary liquid mixtures formed by formamide, N-methylacetamide, di-methylformamide, and di-methylacetamide with acetonitrile at 293.15, 298.15, 303.15, and 313.15 K and atmospheric pressure over the whole concentration range. The Prigogine–Flory–Patterson model, the Ramaswamy and Anbananthan model, the model devised by Glinski, the Sanchez equation, the Goldsack relation, and the Eberhart model were used to predict the associational behaviour of weakly interacting liquids. The measured properties were fitted to the Redlich–Kister polynomial relation to estimate the binary coefficients and standard errors. Furthermore, the McAllister multibody interaction model was used to correlate the binary properties. These nonassociated and associated models were compared and tested for different systems showing that the associated processes yield fair agreement between theory and experiment compared with nonassociated processes.

Surface study of binary mixtures containing chlorinated and oxygenated compounds

We report in this work, experimental surface tensions for binary mixtures of isomeric chlorobutanes with butyl ethyl ether or diisopropyl ether from T=283.15K to 303.15K measured with a drop volume tensiometer. The surface tension data have been correlated with a Redlich–Kister type equation. More information about the surface behaviour can be obtained combining these results with previously reported VLE measurements to calculate the excess surface composition of ether in the mixture. Finally, the results have been compared to the predictions obtained using a group contribution method.

Density, speed of sound, viscosity, refractive index and surface tension of N-methyl-2-pyrrolidone + diethanolamine (or triethanolamine) from T = (293.15 to 323.15) K

Experimental data of density, viscosity, speed of sound, surface tension and refractive index for binary mixtures of N-methyl-2-pyrrolidone with diethanolamine (or triethanolamine) were measured over the entire composition range and for temperatures included between (293.15 and 323.15)K. The effects of mixture composition and temperature, upon these physical properties previously commented, were studied. Different models have been used to fit experimental values of these properties. Derived properties such as excess molar volume, isentropic compressibility and isentropic compressibility excess were calculated. Also, excess molar volumes dependence on composition was fitted using a Redlich–Kister type equation.

Equilibrium and Dynamic Surface Tension of Carboxymethylchitosan and Alkyl Trimethylammonium Bromide Mixtures

A water-soluble derivative of chitosan, carboxymethylchitosan (CMCH), was mixed with alkyltrimethylammoniumbromides (CmTAB) and was studied on the adsorption at air/water interface using equilibrium and dynamic surface tension method. The effects of surfactant and polymer concentrations, surfactant chain length, as well as pH of solution were investigated. Addition of the surfactants remarkably promotes the polymer adsorption. Increasing any one of surfactant concentration, surfactant chain length, and pH will facilitate the adsorption of the mixture whereas little effects of polymer concentration were observed. The results are explained in terms of the interaction between CMCH and CmTAB under different conditions.

Design of an experimental apparatus for measurement of the surface tension of metastable fluids

A unique experimental apparatus for measurement of the surface tension of aqueous mixtures has been designed, manufactured, and tested in our laboratory. The novelty of the setup is that it allows measurement of surface tension by two different methods: a modified capillary elevation method in a long vertical capillary tube and a method inspired by the approach of Hacker ( National Advisory Committee for Aeronautics, Technical Note 2510, 1-20, 1951 ), i.e. in a short horizontal capillary tube. Functionality of all main components of the apparatus, e.g., glass chamber with the capillary tube, temperature control unit consisting of two thermostatic baths with special valves for rapid temperature jumps, helium distribution setup allowing pressure variation above the liquid meniscus inside the capillary tube, has been successfully tested. Preliminary results for the surface tension of the stable and metastable supercooled water measured by the capillary elevation method at atmospheric pressure are provided. The surface tension of water measured at temperatures between +26 °C and –11 °C is in good agreement with the extrapolated IAPWS correlation ( IAPWS Release on Surface Tension of Ordinary Water Substance, September 1994 ); however it disagrees with data by Hacker.