Solvation-based modeling vapor pressures of (solvent plus salt) systems with the application of Cox equation

A solvation model framework, based on the LSER (linear solvation energy relationship) principles, is proposed for correlating vapor pressures of (solvent + salt) systems. The LSER method basely uses a linear combination of several solvatochromic indices of solvents to describe their physical properties. The assumption inherent in the solvation-based vapor pressure approach is attributed to an additional effect of several physical quantities, i.e. the vapor pressure of a pure solvent estimated by the Cox equation, the salt concentration, the solvatochromic indicators of the solvent and the physical properties of the ionic salt species. It has been performed independently two structural forms of the generalized salvation model, i.e. the integrated property-basis model using nine physical descriptors USMIP (the unified solvation model with the integrated properties) and the reduced property-basis one. Also, a simplified concentration-dependent vapor pressure model is presented. The observed vapor pressure data of fifteen (solvent + salt) and two (solvent (1) + solvent (2) + salt) systems have been processed to establish the basis for the model reliability analysis using a log-ratio objective function. The proposed vapor pressure approaches reproduce the observed performance relatively accurately, yielding the overall design factors of 1.065 and 1.072 for the solvation-based models with the integrated and reduced properties and 1.017 for the concentration-based model, respectively. Both the integrated property-basis and reduced property-basis solvation models were able to simulate satisfactorily the vapor pressure data of a binary solvent mixture involving a salt, yielding an overall mean error of 5.7%. (C) 2013 Elsevier B.V. All rights reserved

Extractive removal of Cr(VI) from aqueous acidic media by aliquat 336/xylene system: Optimization and modelling of equilibrium

The extractive removal of Cr (VI) from aqueous sulfate and nitrate solutions by Aliquat 336/xylene system has been studied at 298.2 K and 101.3 kPa. The extraction efficiency of Cr (VI) by Aliquat 336 follow the order H2SO4 > HNO3. The carrier yields a maximum Cr (VI) removal efficiency fixed at the concentration ratio (Aliquat 336/Cr (VI) ≤ 0.5) for 0.1 mol/dm3 aqueous acidity. Separation profile of Cr (VI) is dependent equally strongly on the types and concentrations of the carrier, acid and the transferred Cr (VI) species. Distribution data have been subjected to formulation of an optimization structure for an effective Cr (VI) separation based on a derivative variation method. The method calls for the use the first order derivatives of the optimized quantity. 0.2 mol/dm3 Aliquat 336 concentration is optimal for achieving 99 and 80% Cr (VI) removal from aqueous sulfate and nitrate media, respectively. Re-extraction results indicate that Cr (VI) is stripped successfully from the organic phase by NaOH, NaCl and Na2SO4 solutions, yielding 88, 54.5 and 13.8% stripping degrees, respectively. Modelling efforts based on the LSER (linear solvation energy relation) and mass-action law principles have shown considerable success. The LSER-based solvation model using nine physical descriptors of components yielded a mean error of 10% and satisfies established limiting behaviour of the physical event

Solvation model for estimating the properties of (vapour plus liquid) equilibrium

A solvation energy relation (SERAS) has been developed for correlating the properties and (vapour + liquid) equilibrium (VILE) of associated systems capable of hydrogen bonding or dipole-dipole interaction. The model clarifies the simultaneous impact of hydrogen bonding, solubility and thermodynamic factors of activity coefficients derived from the UNIFAC-original model. The consistency test has been processed against binary VILE data for six isobaric systems of hydrogen bonding (I to III) and dipole-dipole interaction (IV to VI) types, and two isothermal systems of both types (VII and VIII). Systems 11,111, and VIII show negative non-ideal deviations. The reliability analysis has been conducted on the performance of the SERAS model with 5- and 10-parameters. The model matches relatively well with the observed performance, yielding mean error of 9.7% for all the systems and properties considered. (C) 2008 Elsevier Ltd. All rights reserved

Estimation of Vapor Pressures of Solvent plus Salt Systems with Quadratic Solvation Relationships

The paper studies quadratic solvation models (QSMs) applied to the numerical simulation of the vapor pressures of solvent systems with a salt effect. Two useful general quadratic solvation relationships are presented within an integration framework, incorporating cumulative physical indices for components and boundary constraints, in conjunction with the vapor pressures of monomolecular fluids calculated from Antoine, Senol, Frost-Kalkwarf and Xiang-Tan equations. Literature data for the vapor pressures of 18 diverse binary (solvent + salt) and ternary (solvent 1 + solvent 2 + salt 3) vapor-liquid equilibrium systems are subjected to the statistical analysis of QSMs via a logarithmic-ratio objective function and cumulative frequency distribution. Essentially, the examined QSMs with twelve (QSM12) and six (QSM6) adjustable coefficients are quite accurate in yielding overall design factors (F-od) lower than 1.015 and 1.08, respectively. The concentration-dependent model (CM) also simulates precisely the observed data with F-od = 1.013 as far as salt effects are concerned. QSM12 models have proven reasonably successful in predicting the vapor pressures of ternary systems with a mean deviation of 2.2%

Optimization of extractive removal of uranium(VI) from aqueous acidic solutions using commercial amines: Linear solvation energy relation based modeling

The extraction of uranium(VI) from acidic sulfate and nitrate media by Alamine 300 and di-n-octyl amine (DOA) solvents (T=298.2 K) is dependent about equally strongly on the types and concentration levels of the carrier, acid and the transferred U(VI) species. Distribution data have been subjected to formulation of an optimization structure for an effective U(VI) separation on the basis of the derivative variation method. Identification of optimum conditions is governed by the range of changes of the first order derivatives of the optimized quantity. Experimentally and analytically defined optimum U(VI) removal efficiencies of amines are ranging about 70-90% and 30-45% for aqueous-phase sulfate and nitrate media, respectively. Three independent variables, i.e. the concentrations of the carrier, acid and U(VI), are adequate for expressing the non-linear dependence of the optimized extraction factors on the properties of relevant system

Liquid-Liquid Equilibria for Mixtures of (Water plus Pyruvic Acid plus Alcohol/Alamine). Modeling and Optimization of Extraction

Extraction equilibria of the systems (water + pyruvic acid + alcohol/Alamine 336) have been investigated at T = 293.2 K. The solvent mixture of 1-dodecanol/alamine yields the largest separation factors for the extraction of pyruvic acid. An analytical structure for optimum extraction has been developed as the locus of the proposed separation factors. The properties of extraction systems have been correlated by a solvation relation (SERLAS) with 5 and 10 parameters. The tie-lines of the present systems have been predicted by the universal functional activity coefficient (UNIFAC) original model. The reliability analysis of both models has been made statistically against the experimental extraction factors

Optimal Extractive Separation of Chromium(VI) from Acidic Chloride and Nitrate Media by Commercial Amines: Equilibrium Modeling Through Linear Solvation Energy Relation

Data for the extraction of chromium, Cr(VI), from aqueous acidic chloride and nitrate solutions by Alamine 300 (tertiary amine)/xylene and di-n-octyl amine (DOA)/xylene solvent systems (298 K) have been subjected to formulation of an optimization structure for an effective Cr(VI) separation. The optimization approach uses a derivative variation method to efficiently identify the optimization range through analyzing the first-order derivatives of the optimized quantity and the nonlinear deviation profile of the derivative value. The main characteristics of it are simplicity and suitability for generalization. Optimum Cr(VI) removal efficiencies, defined both experimentally and analytically, range from about 70 to 90% for Alamine 300 and from 50 to 70% for DOA, being dependent about equally strongly on the types and concentration levels of the amine, acid, and the transferred Cr(VI) species. These dependencies are rationalized in terms of the interactions that take place in the equilibrium phases. Three independent variables, i.e. the concentrations of the amine, acid, and Cr(VI), are adequate for expressing the nonlinear dependence of the optimized extraction factor (E, Z(t)) on the properties of relevant system. Modeling efforts based on the LSER (linear solvation energy relation) principles and the mass-action law methodology have shown considerable success. The proposed LSER-based solvation model using nine physical descriptors of the solvent and ion provides relatively reliable fits with a mean error of 9%, and satisfies established limiting behavior of the physical event. A critical comparison of the present method with the other commonly used reactive extraction methods on an efficiency basis has been carried out

Predicting Effective Mass Transfer Area in Randomly-packed Column—Design Considerations

777-789The paper describes the performance of a randomly packed distillation column depending on the effective vapor-liquid interfacial area (αc )<span style="font-size:11.5pt;mso-bidi-font-size:7.5pt; font-family:" times="" new="" roman""="" lang="EN-US">and the flood ratio (percent Fl) estimated by the Eckert flooding model. Capacity, pressure gradient, and efficiency data obtained on 6.25 mm size of a Raschig-type ceramic ring are used to establish the basis for the model reliability analysis. The reliability of design models is analyzed against observed performance statistically by using a log-ratio objective function. The proposed <span style="font-size:13.0pt; mso-bidi-font-size:9.0pt;font-family:" times="" new="" roman";mso-fareast-font-family:="" "ms="" mincho""="" lang="EN-US">αc<span style="font-size:13.0pt; mso-bidi-font-size:9.0pt;font-family:" times="" new="" roman""="" lang="EN-US"> approach for random packings is expected to be an improvement in data fit, clarifying the simultaneous impact of packing geometry, loading, and system properties on the performance of a moderate scale packed column. Details underlying some aspects of selection of an appropriate packed column design algorithm are discussed. An example of scaling-up a pilot-plant with respect to the resulting statistical factors is elucidated. Finally, an approach to design in terms of the derivatives of the function <span style="font-size:13.0pt; mso-bidi-font-size:9.0pt;font-family:" times="" new="" roman";mso-fareast-font-family:="" "ms="" mincho""="" lang="EN-US">αc<span style="font-size:9.0pt; mso-bidi-font-size:5.0pt;font-family:" times="" new="" roman""="" lang="EN-US"> = <span style="font-size: 11.5pt;mso-bidi-font-size:7.5pt;font-family:" times="" new="" roman""="" lang="EN-US">f (percent Fl) is interpreted analytically. </span

Extractive removal, of Cr(VI) from aqueous acidic media by aliquat 336/xylene system: Optimization and modelling of equilibrium

The extractive removal of Cr (VI) from aqueous sulfate and nitrate solutions by Aliquat 336/xylene system has been studied at 298.2 K and 101.3 kPa. The extraction efficiency of Cr (VI) by Aliquat 336 follow the order H2SO4 > HNO3. The carrier yields a maximum Cr (VI) removal efficiency fixed at the concentration ratio (Aliquat 336/Cr (VI) <= 0.5) for 0.1 mol/dm(3) aqueous acidity. Separation profile of Cr (VI) is dependent equally strongly on the types and concentrations of the carrier, acid and the transferred Cr (VI) species. Distribution data have been subjected to formulation of an optimization structure for an effective Cr (VI) separation based on a derivative variation method. The method calls for the use the first order derivatives of the optimized quantity. 0.2 mol/dm(3) Aliquat 336 concentration is optimal for achieving 99 and 80% Cr (VI) removal from aqueous sulfate and nitrate media, respectively. Re-extraction results indicate that Cr (VI) is stripped successfully from the organic phase by NaOH, NaCl and Na2SO4 solutions, yielding 88, 54.5 and 13.8% stripping degrees, respectively. Modelling efforts based on the LSER (linear solvation energy relation) and mass-action law principles have shown considerable success. The LSER-based solvation model using nine physical descriptors of components yielded a mean error of 10% and satisfies established limiting behaviour of the physical event

LSER-based modeling vapor pressures of (solvent plus salt) systems by application of Xiang-Tan equation

The study deals with modeling the vapor pressures of (solvent + salt) systems depending on the linear solvation energy relation (LSER) principles. The LSER-based vapor pressure model clarifies the simultaneous impact of the vapor pressure of a pure solvent estimated by the Xiang-Tan equation, the solubility and solvatochromic parameters of the solvent and the physical properties of the ionic salt. It has been performed independently two structural forms of the generalized solvation model, i.e. the unified solvation model with the integrated properties (USMIP) containing nine physical descriptors and the reduced property-basis solvation model. The vapor pressure data of fourteen (solvent + salt) systems have been processed to analyze statistically the reliability of existing models in terms of a log-ratio objective function. The proposed vapor pressure approaches reproduce the observed performance relatively accurately, yielding the overall design factors of 1.0643 and 1.0702 for the integrated property-basis and reduced property-basis solvation models. (C) 2015 The Chemical Industry and Engineering Society of China, and Chemical Industry Press. All rights reserved