Predicting Absorption Equilibria of Mixtures: Comparison of Potential Theory and Ideal Adsorption Solution Theory.

A special free energy function is defined for a solution in the osmotic equilibrium with pure solvent. The partition function of the solution is derived at the McMillan-Mayer level and it is related to this special function in the same manner as the common partition function of the system to its Helmholtz free energy.

Download Full-text

System of thermodynamic quantities in the McMillan-Mayer solution theory

Collection of Czechoslovak Chemical Communications ◽

10.1135/cccc19850791 ◽

1985 ◽

Vol 50 (4) ◽

pp. 791-798 ◽

Cited By ~ 1

Author(s):

Vilém Kodýtek

Keyword(s):

Free Energy ◽

Generating Function ◽

Simple Form ◽

Unit Volume ◽

Thermodynamic Quantities ◽

Solution Theory ◽

Pure Solvent ◽

Second Derivatives ◽

Definition Of ◽

Derivatives Of

The McMillan-Mayer (MM) free energy per unit volume of solution AMM, is employed as a generating function of the MM system of thermodynamic quantities for solutions in the state of osmotic equilibrium with pure solvent. This system can be defined by replacing the quantities G, T, P, and m in the definition of the Lewis-Randall (LR) system by AMM, T, P0, and c (P0 being the pure solvent pressure). Following this way the LR to MM conversion relations for the first derivatives of the free energy are obtained in a simple form. New relations are derived for its second derivatives.

Download Full-text

Adsorption for efficient low carbon hydrogen production: part 2—Cyclic experiments and model predictions

Adsorption ◽

10.1007/s10450-021-00308-w ◽

2021 ◽

Author(s):

Anne Streb ◽

Marco Mazzotti

Keyword(s):

Hydrogen Production ◽

Carbon Capture And Storage ◽

Clean Energy ◽

Separation Performance ◽

Low Carbon ◽

Solution Theory ◽

Feed Composition ◽

Ideal Adsorbed Solution Theory ◽

Adsorbed Solution ◽

Adsorbed Solution Theory

Abstract Hydrogen as clean energy carrier is expected to play a key role in future low-carbon energy systems. In this paper, we demonstrate a new technology for coupling fossil-fuel based hydrogen production with carbon capture and storage (CCS): the integration of CO2 capture and H2 purification in a single vacuum pressure swing adsorption (VPSA) cycle. An eight step VPSA cycle is tested in a two-column lab-pilot for a ternary CO2–H2–CH4 stream representative of shifted steam methane reformer (SMR) syngas, while using commercial zeolite 13X as adsorbent. The cycle can co-purify CO2 and H2, thus reaching H2 purities up to 99.96%, CO2 purities up to 98.9%, CO2 recoveries up to 94.3% and H2 recoveries up to 81%. The key decision variables for adjusting the separation performance to reach the required targets are the heavy purge (HP) duration, the feed duration, the evacuation pressure and the flow rate of the light purge (LP). In contrast to that, the separation performance is rather insensitive towards small changes in feed composition and in HP inlet composition. Comparing the experimental results with simulation results shows that the model for describing multi-component adsorption is critical in determining the predictive capabilities of the column model. Here, the real adsorbed solution theory (RAST) is necessary to describe all experiments well, whereas neither extended isotherms nor the ideal adsorbed solution theory (IAST) can reproduce all effects observed experimentally.

Download Full-text

Effective Separation of Prime Olefins from Gas Stream Using Anion Pillared Metal Organic Frameworks: Ideal Adsorbed Solution Theory Studies, Cyclic Application and Stability

Catalysts ◽

10.3390/catal11040510 ◽

2021 ◽

Vol 11 (4) ◽

pp. 510

Author(s):

Majeda Khraisheh ◽

Fares. Almomani ◽

Gavin Walker

Keyword(s):

Breakthrough Curves ◽

Isotherm Models ◽

Regeneration Ability ◽

Solution Theory ◽

Experimental Conditions ◽

Ideal Adsorbed Solution Theory ◽

Adsorbed Solution ◽

The Stability ◽

Adsorption Desorption ◽

Adsorbed Solution Theory

The separation of C3H4/C3H6 is one of the most energy intensive and challenging operations, requiring up to 100 theoretical stages, in traditional cryogenic distillation. In this investigation, the potential application of two MOFs (SIFSIX-3-Ni and NbOFFIVE-1-Ni) was tested by studying the adsorption–desorption behaviors at a range of operational temperatures (300–360 K) and pressures (1–100 kPa). Dynamic adsorption breakthrough tests were conducted and the stability and regeneration ability of the MOFs were established after eight consecutive cycles. In order to establish the engineering key parameters, the experimental data were fitted to four isotherm models (Langmuir, Freundlich, Sips and Toth) in addition to the estimation of the thermodynamic properties such as the isosteric heats of adsorption. The selectivity of the separation was tested by applying ideal adsorbed solution theory (IAST). The results revealed that SIFSIX-3-Ni is an effective adsorbent for the separation of 10/90 v/v C3H4/C3H6 under the range of experimental conditions used in this study. The maximum adsorption reported for the same combination was 3.2 mmolg−1. Breakthrough curves confirmed the suitability of this material for the separation with a 10-min gab before the lighter C3H4 is eluted from the column. The separated C3H6 was obtained with a 99.98% purity.

Download Full-text

Potential Theory

Introduction to Stellar Dynamics ◽

10.1017/9780511736117.002 ◽

2021 ◽

pp. 1-2

Keyword(s):

Potential Theory

Download Full-text

Sorption of phenols on hexadecyltrimethylammonium- modified bentonite: Application of Polanyi−Manes potential theory

Energy & Environment ◽

10.1177/0958305x20977286 ◽

2020 ◽

pp. 0958305X2097728

Author(s):

Jiyeon Choi ◽

Dong-Ik Slong ◽

Won Sik Shin

Keyword(s):

Molar Volume ◽

Potential Theory ◽

Characteristic Curve ◽

Chemical Compositions ◽

Pore Filling ◽

Sorption Data ◽

Similar Chemical ◽

Competitive Model ◽

Sorption Potential ◽

Sorption Systems

This study investigated the sorption of phenol and 4-chlorophenol (4-CP) on natural bentonite modified with hexadecyltrimethylammonium (HDTMA) cation. The Freundlich, Langmuir, Dubinin−Radushkevich (DR), Sips, and Polanyi−Dubinin−Manes (PDM) models fitted the sorption data well (R2 > 0.92). The Freundlich coefficient and the maximum sorbed amount of the Langmuir and PDM models of 4-CP were higher than phenol because of higher hydrophobicity (log Kow = 2.39 for 4-CP and 1.46 for phenol). The PDM model that includes solubility and molar volume was highly useful in predicting the sorption of phenols having widely different hydrophobicity and solubility. The characteristic curves, the plot of sorbed volume ( qv) versus the sorption potential per molar volume ( ε/ Vm) of 4-CP and phenol were distinctly different although they have similar chemical compositions. The selectivity of 4-CP (3.72) was higher than that of phenol (0.27) in binary sorption systems. The sorbed volume ( qv) in the binary sorption was remarkably reduced and the characteristic curve had wider distribution owing to competition in pore-filling. The sorption behaviors were elucidated by partitioning and pore-filling mechanisms. Among the tested binary sorption models, the modified Langmuir competitive model was the best in the prediction of the binary sorption (R2 > 0.98).

Download Full-text