Fatemeh Sabzi

Shiraz University of Technology, Chemical Engineering, Faculty Member

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Sorption of CO2, C2H2 and C2H4 in HOF-1a studied by PHSC equation of state

Fluid Phase Equilibria, Dec 1, 2013

Acetylene is a byproduct of modern ethylene production by cracking of hydrocarbons. There are ext... more Acetylene is a byproduct of modern ethylene production by cracking of hydrocarbons. There are extensive research efforts to exchange solvent extraction and hydrogenation methods for removing acetylene from ethylene with cost-effective membrane separation technology. Recently, the first Hydrogen-bonded Organic Framework (HOF) has been established to examine its capacity for acetylene uptake. In this study, Perturbed Hard Sphere Chain equation of state (PHSC) has been selected to obtain volumetric data for CO 2 , C 2 H 2 and C 2 H 4 sorption on HOF-1a system. Three molecular-based parameters including hardsphere diameter (), the non-bonded interaction energy (ε) and number of segments per molecule (r) have been employed as scaling constants and calculated using group contribution (GC) method. High capacity of HOF-1a has been demonstrated for C 2 H 2 /C 2 H 4 separation. C 2 H 2 and C 2 H 4 coupling effects in the mixed gas sorbed in HOF-1a, have been extracted from PHSC EoS for mixture sorption. The sorption of acetylene decreases in the presence of ethylene while sorption of ethylene increases in the presence of acetylene. HOF-1a has high capacity to sorb C 2 H 2 as an impurity in industrial gas separation, but its low selectivity causes the loss of ethylene which makes it economically detrimental.

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Gas Transport Through Polymer Blends

Transport Properties of Polymeric Membranes

Polymeric membranes are convenient materials for gas separation processes such as natural gas swe... more Polymeric membranes are convenient materials for gas separation processes such as natural gas sweetening, hydrogen purification, and air separation because they offer a simple, easy-to-operate, low-maintenance process option. However, their further development has been constrained by a performance trade-off between gas permeability and selectivity. Researchers fabricated new products by blending glassy and rubbery polymers and examined their gas separation efficiency. Here, the most recently developed polymer blends and gas transport through them have been reviewed and the mutual effects of gas transport phenomena and polymer blend composition on each other have been evaluated. It has been concluded that gas permeability increases and gas selectivity decreases as the concentration of more permeable polymer in the blend increases. The gas selectivity increases with chemical cross-linking and with decreasing temperature. The gas selectivity also decreases with pressure where CO 2 plasticization occurs.

Theoretical Aspects of Gas Transport in Polymers

Applications of gas diffusion in polymers have become very important in today's life and play... more Applications of gas diffusion in polymers have become very important in today's life and play an essential and controlling role in many usages, such as gas purification and treatment processes of exhausted gases from industries and automobiles. Therefore, a better understanding of gas diffusion phenomena through polymers is more practical. In this chapter, after the presentation of general considerations and basic mathematical equations, some of the most important theoretical models that have been developed up to now for describing the concept of gas transport in polymer materials are reviewed. According to many studies that have been done in this area, the comparison of diffusion mechanisms, which depend on polymer structures and process conditions such as temperature and pressure, is provided.

Molecular Dynamics Simulation of CO2 Adsorption and Diffusion in UTSA-16

International Journal of Thermodynamics, 2021

Molecular dynamics simulation has been employed to calculate the amounts of adsorption and diffus... more Molecular dynamics simulation has been employed to calculate the amounts of adsorption and diffusion of CO2 in a type of MOF named UTSA-16. The UTSA-16 has been chosen in this work due to high active water molecules coordinated in its structure which strengthen CO2 interaction and enhances its sorption capacity. Effects of temperatures 298, 313 and 338 K and pressures up to 40 bar on the simulated adsorption properties and also on the diffusion coefficients have been elucidated. To shed light on the mechanism of microscopic phenomena, mean square displacement (MSD) and density profile analyses have been provided and discussed. It has been found that the amount of carbon dioxide adsorption increases with pressure enhancement and temperature reduction. The evaluation of density profile shows the disorder distribution of CO2 molecules through simulation box at lower pressure and their association in the center of the box at higher pressure. The slope of the MSD value increases with increasing pressure and decreasing temperature. As a result, CO2 diffusion coefficient decreases with temperature and increases with pressure.

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Prediction of CO2 and H2 solubility, diffusion, and permeability in MFI zeolite by molecular dynamics simulation

Structural Chemistry, 2021

Molecular dynamics simulation has been employed to calculate the amounts of solubility, diffusion... more Molecular dynamics simulation has been employed to calculate the amounts of solubility, diffusion coefficient, and permeability for the pure and volumetric binary mixture of CO2 and H2 in MFI (Mobil-FIve) zeolite and the effect of pressure and temperature on the observed transport properties. It has been found that the amount of carbon dioxide adsorption is much more than the amount of hydrogen adsorption and MFI zeolite adsorbs higher amount of both gases with pressure enhancement and temperature reduction. The MSD (mean square displacement) value for the hydrogen is much higher than that of carbon dioxide. The variation of the diffusion coefficient of carbon dioxide and hydrogen gas with pressure does not obey a certain trend, but temperature enhancement has a direct effect on the diffusion coefficient of both gases. It is also noticeable that the diffusion coefficient of hydrogen molecules in the gaseous mixture is lower than that in pure state, and vice versa is true for carbon dioxide. The CO2 permeability decreases with increasing pressure, but H2 permeability is not affected by the pressure. The permeability of CO2 molecules decreases and the permeability of H2 molecules increases with increasing temperature.

Thermodynamic modeling of hydrogen solubility in a series of ionic liquids

International Journal of Hydrogen Energy, 2018

In this study, the Perturbed Hard Sphere Chain Equation of State (PHSC EoS) has been employed to ... more In this study, the Perturbed Hard Sphere Chain Equation of State (PHSC EoS) has been employed to predict the hydrogen solubility in a series of ionic liquids. As ionic liquids have no vapor pressure and no critical parameters and as hydrogen is a light molecule which behaves like a perfect gas, simple cubic equations of state cannot be used for modeling of H 2 þ ionic liquid mixture. Three main parameters of non-cubic PHSC EoS, i.e. (r) the number of segments per molecule, ðsÞ the distance between two molecules at zero potential and ðεÞ well-depth of potential between two non-bonded units have been calculated by regression of the experimental Pressure-Volume-Temperature (PVT) data points. The hydrogen solubility decreases with increasing temperature in [BMIM][BF 4 ], [BMIM][C 8 SO 4 ], [EMIM][EtSO 4 ], [MDEA][Cl], and [N 4,1,1,1 ][Tf 2 N], but inverse temperature effect is observed in [BMIM], [BMPY], [EMIM] and [HMIM][Tf 2 N] as well as [BMIM][MeSO 4 ]. The binary interaction parameter which has been obtained from fitting of the equation of state with experimental hydrogen absorption data shows both the usual and the opposite trend of temperature effect as well.

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Prediction of CO 2 sorption in poly(ionic liquid)s using ANN-GC and ANFIS-GC models

International Journal of Greenhouse Gas Control, 2017

In the present work, group contribution method (GC) together with the Artificial Neural Network (... more In the present work, group contribution method (GC) together with the Artificial Neural Network (ANN) and Artificial Neuro-Fuzzy Inference System (ANFIS) models have been used to predict the carbon dioxide sorption in several Poly Ionic Liquids (PILs). A number of PILs based on ammonium and imidazolium by different anion and cation parts have been investigated based on a dataset containing 35 PILs with 350 data points. 70% of data points have been used for training the network, 25% for testing and 5% for validation. The model is a multilayer Feed Forward Artificial Neural Network (FFANN) with Levenberg-Marquardt as a function for optimizing error. The number of optimum neurons in the hidden layer is equal to 20. To distinguish PILs from each other, their structure has been defined by group contribution method. In addition of type and number of the chemical structures, pressure (bar) and temperature (K) have been also fed as input parameters to the network. Amount of carbon dioxide sorption in terms of concentration has been defined as the output of the network. The Absolute Average Deviation (AAD%) indicates that the ANN-GC and ANFIS-GC models are appropriate tools to predict carbon dioxide solubility where ANN-GC model shows sign of some superiority.

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Methane Adsorption in a Series of IRMOFs Studied by PHSC and Sanchez–Lacombe Equations of State

Journal of Inorganic and Organometallic Polymers and Materials, 2015

ABSTRACT In this study, the methane adsorption on several kinds of isoreticular metal organic fra... more ABSTRACT In this study, the methane adsorption on several kinds of isoreticular metal organic frameworks (IRMOF) has been modeled by applying perturbed hard sphere chain (PHSC) and Sanchez-Lacombe (SL) equation of state. PHSC and SL equation of state have three characteristic parameters calculated using group contribution method. In this study, the methane adsorption on absorbents, namely, IRMOF-6, IRMOF-8, IRMOF-10, IRMOF-14 has been obtained at temperature 298 K and various pressures up to 10 MPa. Finally, results have been compared with the simulated adsorption data points to show the precision of PHSC and SL equation of state in predicting the methane sorption trend.

Prediction of solubility of sulfur dioxide in ionic liquids using artificial neural network

Journal of Molecular Liquids, 2015

Abstract In this work, artificial neural network (ANN) has been used to estimate the solubility o... more Abstract In this work, artificial neural network (ANN) has been used to estimate the solubility of sulfur dioxide in different ionic liquids. The studied ionic liquids are consisting of 1-butyl-3-methylimidazolium acetate [BMIM][Ac], 1-n-butyl-3-methylimidazolium methylsulfate [BMIM][MeSO 4 ], 1-Butyl-3-methylimidazolium tetrafluoroborate ([BMIM][BF 4 ]), 1-butyl-3-methylimidazolium hexafluorophosphate ([BMIM][PF 6 ]), 1-butyl-3-methylimidazolium bis(trifluoromethylsulfonyl) imide [BMIM][Tf 2 N], 1-ethyl-3-methylimidazolium tetrafluoroborate ([EMIM][BF 4 ]), 1-Hexyl-3-methylimidazolium tetrafluoroborate ([HMIM][BF 4 ]) and 1-Hexyl-3-methylimidazolium bis(trifluoromethylsulfonyl)imide [HMIM][Tf 2 N]. The model has five inputs including temperature, pressure, critical temperature, critical pressure and acentric factor. The network has been trained with about 70% of data sets and tested with other 30% of data points. The most accurate network has one hidden layer with 27 neurons. The results of this study show that the ANN model is successful in estimation of the solubility of sulfur dioxide in ionic liquids.

The ISM Equation of State Applied to Refrigerants

International Journal of Thermophysics, 1999

In this work, we apply an equation of state based on statistical–mechanical perturbation theory t... more In this work, we apply an equation of state based on statistical–mechanical perturbation theory to liquid refrigerants and their mixtures. Three temperature-dependent parameters are needed to use the equation of state: the second virial coefficient, B2(T), an effective van der Waals covolume, b(T), and a scaling factor, a(T). The second virial coefficients are calculated from a correlation based on the

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Sorption of methane in a series of Zn-based MOFs studied by PHSC equation of state

Fluid Phase Equilibria, 2014

Adsorption and storage of gaseous methane as a clean fuel for cars has always attracted the atten... more Adsorption and storage of gaseous methane as a clean fuel for cars has always attracted the attention of researchers. One of the most famous porous absorbents which has been used for separation and storage of several gases is called metal organic framework (MOF). These kinds of absorbents have been intensely studied in recent years. In this study, the experimental data related to methane adsorption on and desorption from five absorbents, namely, MOF-5, MOF-177, MOF-200, MOF-205 and MOF-210 have been adopted. Then, the methane sorption has been modeled by applying Perturbed Hard Sphere Chain Equation of State (PHSC EoS). PHSC equation of state has three molecular-based parameters, r, and ; which are the number of segments per molecule, the hard-sphere diameter and the non-bonded interaction energy, respectively. These three parameters have been calculated using group contribution (GC) method. The amount of methane uptake in the adsorbents has been obtained through gas-absorbents phase equilibrium calculations at temperature 298 K and various pressures up to 90×10 5 Pa. Finally, results have been compared with the experimental data to show the precision of PHSC equation of state in predicting the methane sorption trend.

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Prediction of water vapor sorption in the polymeric membranes using PHSC equation of state

Journal of Natural Gas Science and Engineering, 2014

ABSTRACT

Water Sorption and Solvent Sorption Behavior

Characterization of Polymer Blends, 2014

Modeling of thermodiffusion in liquid metal alloys

Physical Chemistry Chemical Physics, 2010

In this paper following the linear non-equilibrium thermodynamics approach, an expression is deri... more In this paper following the linear non-equilibrium thermodynamics approach, an expression is derived for the calculation of the thermodiffusion factor in binary liquid metal alloys. The expression is comprised of two terms; the first term accounts for the thermally driven interactions between metal ions, a phenomenon similar to that of the non-ionic binary mixtures, such as hydrocarbons; the second term is called the electronic contribution and is the mass diffusion due to an internal electric field that is induced as a result of the imposed thermal gradient. Both terms are formulated as functions of the net heats of transport. The ion-ion net heat of transport is simulated by the activation energy of viscous flow and the electronic net heat of transport is correlated with the force acting on the ions by the rearrangement of the conduction electrons and ions. A methodology is presented and used to estimate the liquid metal properties, such as the partial molar internal energies, enthalpies, volumes and the activity coefficients used for model validation. The prediction power of the proposed expression along with some other existing thermodiffusion models for liquid mixtures, such as the Haase, Kempers, Drickamer and Firoozabadi formulas are examined against available experimental data obtained on ground or in microgravity environment. The proposed model satisfactorily predicts the thermodiffusion data of mixtures that are composed of elements with comparable melting points. It is also potentially and qualitatively able to predict a sign change in thermodiffusion factor of Na-K liquid mixture. With some speculation, the sign change is attributed to an anomalous change in thermoelectric power of Na-K mixture with composition.

Modified perturbed hard-sphere equation of state for alkali metal alloys

Journal of Non-Crystalline Solids, 2006

A modified perturbed hard-sphere equation of state has been applied to calculate the liquid densi... more A modified perturbed hard-sphere equation of state has been applied to calculate the liquid density of alkali metal alloys. Two scaling parameters e and r are sufficient to calculate the temperature-dependent parameters of equation of state a(T) and b(T) that are universal functions of the reduced temperature. Calculations cover a broad range of temperature from melting point close to critical point. In this work, we have extended the present correlation to mixtures of any number of components. The predicted results for the liquid density of K-Cs and Na-K alloys over the whole range of concentrations are in good agreement with experimental data. From 220 data points examined for molten alloys deviations are within about 5%.

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Compatibility of polymer blends. I. Copolymers with organic solvents

Journal of Applied Polymer Science, 2006

ABSTRACT: In this work, we present a theoretical dis-cussion regarding the FloryHuggins interact... more

Sorption of CO2, C2H2 and C2H4 in HOF-1a studied by PHSC equation of state

Fluid Phase Equilibria, 2013

ABSTRACT Acetylene is a byproduct of modern ethylene production by cracking of hydrocarbons. Ther... more ABSTRACT Acetylene is a byproduct of modern ethylene production by cracking of hydrocarbons. There are extensive research efforts to exchange solvent extraction and hydrogenation methods for removing acetylene from ethylene with cost-effective membrane separation technology. Recently, the first Hydrogen-bonded Organic Framework (HOF) has been established to examine its capacity for acetylene uptake. In this study, Perturbed Hard Sphere Chain equation of state (PHSC) has been selected to obtain volumetric data for CO2, C2H2 and C2H4 sorption on HOF-1a system. Three molecular-based parameters including hard-sphere diameter (σ), the non-bonded interaction energy (ɛ) and number of segments per molecule (r) have been employed as scaling constants and calculated using group contribution (GC) method. High capacity of HOF-1a has been demonstrated for C2H2/C2H4 separation. C2H2 and C2H4 coupling effects in the mixed gas sorbed in HOF-1a, have been extracted from PHSC EoS for mixture sorption. The sorption of acetylene decreases in the presence of ethylene while sorption of ethylene increases in the presence of acetylene. HOF-1a has high capacity to sorb C2H2 as an impurity in industrial gas separation, but its low selectivity causes the loss of ethylene which makes it economically detrimental.

Application of the ISM EoS for polymer melts

European Polymer Journal, 2004

A method for predicting an analytical equation of state for polymer melts from surface tension an... more A method for predicting an analytical equation of state for polymer melts from surface tension and liquid state density at the freezing temperature ðc f ; q f Þ, as scaling constants, is presented. B 2 ðT Þ follows a promising correspondingstates principle. Calculation of aðT Þ and bðT Þ, the two other temperature-dependent constants of the equation of state, are made possible by scaling. As a result, c f and q f are sufficient for the calculation of thermophysical properties of polymer melts. We applied the procedure to predict specific volumes of polyethylene glycol (PEG), polypropylene glycol (PPG), polypropylene (PP) and polyvinylchloride (PVC) at compressed state with temperature range from 298.15 to 423.15 K and pressures up to 200 MPa. The experimental specific volumes were correlated satisfactorily with our procedure and the results are within 3%.

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Application of the ISM EoS for polymer solutions and blends

European Polymer Journal, 2004

A method for predicting an analytical equation of state for polymer mixtures and blends from surf... more

Sorption phenomena of organic solvents in polymers: Part I

European Polymer Journal, 2005

In this work we use the vapor-sorption equilibrium data to show the degree of solvent upturn in e... more In this work we use the vapor-sorption equilibrium data to show the degree of solvent upturn in each solvent-polymer system. For this purpose, sixty-one isothermal data sets for forty copolymer + solvent binaries and for fourteen of their parent homopolymer + solvent binaries have been used in the temperature range of 23.5-80°C. Solvents studied are acetone, acetonitrile, 1-butanol, 1,2-dichloroethane, chloroform, cyclohexane, hexane, methanol, octane, pentane, and toluene. Copolymers studied are poly(acrylonitrile-co-butadiene), poly(styrene-co-acrylonitrile), poly(styreneco-butadiene), poly(vinyl acetate-co-ethylene), and poly(vinyl acetate-co-vinyl chloride). All copolymers are random copolymers. Some homopolymers are also studied: polyacrylonitrile, poly(cis-1,4-butadiene), poly(ethylene oxide), polystyrene and poly(vinyl acetate). According to these data sets, solvent weight fraction in the polymer is plotted against solvent vapor activity that is calculated assuming an ideal gas phase of pure solvent vapor neglecting the vapor pressure of the polymer. We use the Flory-Huggins theory to obtain dimensionless interaction parameter, v. Also the Zimm-Lundberg clustering theory and non-ideality thermodynamic factor, C are used to interpret the equilibrium data.

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Fatemeh Sabzi

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