Density Of Aqueous Electrolyte Solutions Research Articles

The implementation of ion-based ePC-SAFT EOS for calculation of the mean activity coefficient of single and mixed electrolyte solutions

Following our previous work (Journal of Molecular Liquids 221 (2016) 904–913), the modified perturbed chain statistical associating fluid theory (ePC-SAFT) incorporated with Debye-Huckel term has been applied to calculate some thermodynamic properties of single and mixed electrolyte solutions. The applicability of this model has been investigated by calculation of the mean ionic activity and osmotic coefficients of electrolyte solutions as well as the water activity of regarded systems at different temperatures. Firstly, water-ion hydration has been taken into account independently by two individual strategies, i.e. ions can be considered as non-associating and associating compounds distinctly. Afterwards, a new set of ion parameters containing 31 common ions has been estimated using the experimental mean ionic activity coefficients and liquid densities of 78 binary electrolyte solutions in both strategies. The optimized parameters which have been utilized for prediction of single-salt aqueous electrolyte solutions MIACs up to 373.15 K are global and transferable to different salts. Eventually, it can be observed that not only the density of aqueous electrolyte solutions, but also MIACs, osmotic coefficients and water activity of single and mixed salt solutions are satisfactorily calculated by considering ions as association compounds over a wide range of temperature and salt concentration.

Application of ion-based ePC-SAFT in prediction of density of aqueous electrolyte solutions

An electrolyte equation of state based on PC-SAFT in conjunction with Debye-Huckel term has been utilized for calculating the density of aqueous electrolyte solutions using two different strategies. In the first manner, the association interaction between water and ions does not consider, while in the second strategy, the associative hydrogen-bonding behavior between ions and water are implemented. Using the experimental densities of 80 binary aqueous electrolyte solutions including 31 common ions, ion parameters have been optimized by a global optimization method. The corresponding results of both strategies are presented and compared with the experimental density of single and mixed electrolyte solutions up to 373.15K. Furthermore, the estimated individual ion parameters have been reasonably extended to predict different properties of multicomponent electrolyte solutions. Finally, by comparing the obtained average relative deviations of densities for binary solutions, it can be observed that the density is satisfactorily calculated with considering ions as associating compounds (Overall ARD~0.8).

Correlations for Densities of Aqueous Electrolyte Solutions

We present simple %-level accuracy universal correlations for densities of aqueous electrolyte solutions at 298.15 K and 0.1 MPa. The developed expressions and parameters are based on 1032 experimental density data points for 56 aqueous single electrolyte solutions including chlorides, bromides, iodides, bicarbonates, carbonates, sulfates, nitrates, nitrites, phosphates, hydrogen phosphates, and dihydrogen phosphates. The correlations relate the solution density with “excess” mass fraction of electrolytes in solution. With molar mass and concentrations of electrolytes as input, the correlation yields density results for all 56 electrolytes with the average error of 0.97% and the maximum error of 8.05%. When grouping the electrolytes as either structure making, structure breaking, or structure superbreaking, the correlations yield the average error of 0.59% and the maximum error of 3.45%. The correlations should be very useful in estimating the density of aqueous single and multicomponent electrolyte solut...

Experimental and Modeling Studies on the Densities of Aqueous Solutions of 1-Carboxymethyl-3-methylimidazolium Chloride, 1-Carboxymethyl-3-propylimidazolium Chloride, and 1-(2-Hydroxylethyl)-3-propylimidazolium Chloride at (293.15, 298.15, and 303.15) K

The densities of the binary aqueous solutions of 1-carboxymethyl-3-methylimidazolium chloride ([HOOCMMIm]Cl), 1-carboxymethyl-3-propylimidazolium chloride ([HOOCMPIm]Cl), 1-(2-hydroxylethyl)-3-propylimidazolium chloride ([HOEtPIm]Cl), and the ternary solutions [HOOCMMIm]Cl + [HOOCMPIm]Cl + H2O, [HOEtPIm]Cl + [HOOCMPIm]Cl + H2O, and [HOEtPIm]Cl + [HOOCMMIm]Cl + H2O have been measured at (293.15, 298.15, and 303.15) K, respectively. The densities of the examined ternary solutions have been predicted by the equation of Patwardhan and Kumar established for the density of aqueous electrolyte solutions. The predictions were not very satisfactory probably due to the presence of the functional group −COOH. The coupling of the Patwardhan and Kumar’s equation and the rule of Young and Smith considerably improves the predictions, and the predicted results show excellent agreements with the experimental results.

Rescaled Specific Volume Model for Electrolyte Solution Density

A very useful model, the Lalibertè–Cooper (LC) model, for predicting densities for electrolyte mixtures has been previously reported that scales with mass fraction or molal electrolyte concentrations (Lalibertè, M.; Cooper, W. E. Model for Calculating the Density of Aqueous Electrolyte Solutions. J. Chem. Eng. Data2004, 49, 1141–51). This model proves to be very useful in predicting densities of even very complex mixtures such as high level waste liquids at the Hanford Site. Moreover, a straightforward rescaling of the LC model results in a much more intuitive basis. As a result, this rescaled LC (RLC) model reveals much insight into the free energy changes associated with electrolyte specific volumes. Moreover the introduction of an additional parameter for total cation scaling extends the RLC to molar concentrations.

A New Hydration Model in Correlating the Mean Ionic Activity Coefficient and Density of Aqueous Electrolyte Solutions

In this article, a new hydration model has been proposed to study the phase behavior of aqueous electrolyte solutions. The proposed model distinguishes between an anion and cation in the electrolyte solution. The model has three adjustable parameters which can be obtained using the experimental data of the mean ionic activity coefficients for 113 electrolyte solutions. The results of the proposed model were compared with those of obtained from the Pitzer, the E-NRTL and the E-Wilson models. The results showed that the proposed model can accurately correlate the mean ionic activity coefficients of the aqueous electrolyte solutions than the other models. Also, the proposed model was used in obtaining the density for a number of aqueous electrolyte solutions. The results obtained for the density of electrolyte solutions studied in this work indicated that there are very good agreement between the experimental data and the results of the proposed model.

Extension of the Dense System Equation of State to Electrolyte Solutions

In this work we have applied the Dense System Equation of State (DSEOS) to electrolyte solutions. We have found that this equation of state can predict the density of electrolyte solutions very accurately. It has been tested for different electrolytes solutions at different temperatures and compositions. A hypothetical binary model has been applied to find the dependencies of parameters of this equation of state on solution temperature and composition. Using such a simple model the heat capacity of NaCl solution was calculated for which the absolute percent deviation is less than 2 %. The DSEOS is tested for the following electrolytes: Na2SO4, MgCl2, MgSO4, KCl, NaCl, and NaBr. We found that the DSEOS predicts the density of aqueous electrolyte solutions mentioned above accurately so that its percent error in density is less than 0.04.

Model for Calculating the Density of Aqueous Electrolyte Solutions

AbstractFor Abstract see ChemInform Abstract in Full Text.

Model for Calculating the Density of Aqueous Electrolyte Solutions

A new model for calculating the density of aqueous solutions of electrolytes has been developed. Parameters for 59 electrolytes were established on the basis of an extensive critical review of the published literature for solutions of one electrolyte in water, with over 10 700 points included. The average difference between the calculated and experimental density of solutions of water and one electrolyte is 0.10 kg m-3 with a standard deviation of 1.44 kg m-3. The model was validated by predicting the density of systems of two or more electrolytes in water. The average difference between experimental and calculated values for over 1600 points is 0.003 kg m-3 with a standard deviation of 1.39 kg m-3. The electrolytes studied are AlCl3, Al2(SO4)3, BaCl2, CaCl2, CdCl2, CdSO4, CoCl2, CoSO4, CrCl3, Cr2(SO4)3, CuCl2, CuSO4, FeCl2, FeSO4, FeCl3, Fe2(SO4)3, HCl, HCN, HNO3, H3PO4, H2SO4, KCl, K2CO3, KNO3, KOH, K2SO4, LiCl, Li2SO4, MgCl2, MgSO4, MnCl2, MnSO4, NaBr, NaCl, NaClO3, Na2CO3, NaF, NaHCO3, NaH2PO4, Na2HPO...

Extension of self-consistent local-composition models for correlation of densities of aqueous electrolyte solutions

Expressions for the excess volume of electrolyte solutions are obtained for the self-consistent local-composition (SCLC) model and the modified SCLC (MSCLC) model. Applicability of obtained equations in the correlation of the densities of aqueous solutions of different kinds of salts (1:1, 2:1, 1:2 and 2:2) at 298 K is examined. It is found that the both original and modified SCLC models are suitable models in representing the published density data for the tested aqueous salt solutions. The results obtained from these models were compared with those obtained from the non-random two liquid (NRTL) and the Pitzer models.

A simple method for modelling and prediction of the specific heat and density of aqueous electrolyte solutions

A requirement for numerous applications of electrolyte solutions is the knowledge of the properties for as many as possible substances in a maximum range of concentration, although often with limited accuracy. Semiempirical methods, created through the knowledge of similarities in an analogue group of electrolytes offer an easy way to predict certain data for concentration ranges and electrolyte solutions not covered by measurements of these properties. It could be shown that specific heat and density of aqueous electrolyte solutions can be described by means of a single parameter method, based on the scaling of the molality axis, thus generating a general reference function. Knowing this function and the affiliated scale factor, which gives the so called “effectiveness coefficient”, values of the respective property are available over the whole range of concentration. Also, a method is described to estimate the effectiveness coefficient for uninvestigated electrolytes.

Calculation of densities of aqueous electrolyte solutions at subzero temperatures

We developed a FORTRAN program based on the Pitzer equations to calculate densities of electrolyte solutions at subzero temperatures. Data from the published literature collected at -28.9, -17.8, -12.2, -6.7, 0, and 25°C were used to calculate the Pitzer-equation parameters and to evaluate model performance. Three approaches to estimating the molar volume of the solute at infinite dilution were evaluated: (1) extrapolation of apparent molar volumes to zero square-root ionic strength; (2) calculation with the Tanger and Helgeson model; and (3) global fit of the data in which the molar volume of the solute at infinite dilution was estimated along with the Pitzer-equation parameters. The last approach gave parameter estimates that reproduced the experimental data most accurately. The parameterized model predicted accurately densities of single-electrolyte and multielectrolyte solutions at -28.9, -17.8, -12.2, -6.7, 0, and 25°C. Available experimental data are generally quite poor. Accordingly, Pitzer-equation parameters estimated for subzero temperatures should be viewed as conditional until improved measurements of single-electrolyte solution densities at subzero temperatures are made.

Densities of aqueous electrolyte solutions. A model for a data bank

ADVERTISEMENT RETURN TO ISSUEPREVArticleNEXTDensities of aqueous electrolyte solutions. A model for a data bankIvan Horsak and Ivo SlamaCite this: J. Chem. Eng. Data 1986, 31, 4, 434–437Publication Date (Print):October 1, 1986Publication History Published online1 May 2002Published inissue 1 October 1986https://doi.org/10.1021/je00046a018RIGHTS & PERMISSIONSArticle Views202Altmetric-Citations4LEARN ABOUT THESE METRICSArticle Views are the COUNTER-compliant sum of full text article downloads since November 2008 (both PDF and HTML) across all institutions and individuals. These metrics are regularly updated to reflect usage leading up to the last few days.Citations are the number of other articles citing this article, calculated by Crossref and updated daily. Find more information about Crossref citation counts.The Altmetric Attention Score is a quantitative measure of the attention that a research article has received online. Clicking on the donut icon will load a page at altmetric.com with additional details about the score and the social media presence for the given article. Find more information on the Altmetric Attention Score and how the score is calculated. Share Add toView InAdd Full Text with ReferenceAdd Description ExportRISCitationCitation and abstractCitation and referencesMore Options Share onFacebookTwitterWechatLinked InReddit PDF (401 KB) Get e-Alerts Get e-Alerts

The temperature of maximum density of aqueous electrolyte solutions and its relation to the temperature derivative of the partial molar volume of the solute

The change of the temperature of maximum density from that of pure water divided by the molality of the solution, the Despretz constant, has been measured for solutions of calcium chloride and of barium chloride. It is shown how the Despretz constant can be used to calculate values of ∂ V ∞ 2 /∂ T , where V ∞ 2 denotes the partial molar volume of the electrolyte at infinite dilution, which agree well with those obtained directly from measurements of density.

Computation of the radius and the polarizability of a number of ions

AbstractFrom measurements of the refractive index and the density of aqueous electrolyte solutions, the radius and the polarizability of the ions Cl−, Br−, I, NO3−, ClO4−, SO4−, NH4+, Rb+, Cs+, Sr++ and Ba++ are calculated, also the polarizability of the ions Na+, K+ and Ca++.