Temperature effects on the retention of n-alkanes and arenes in helium–squalane gas–liquid chromatography

Wick, Collin D.; Siepmann, J. Ilja; Klotz, Wendy L.; Schure, Mark R.

doi:10.1016/s0021-9673(02)00171-1

Cited by 70 publications

(95 citation statements)

References 34 publications

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“…The various aspects of sub-critical benzene adsorption have been covered by Do and Do (2006a). From this study it was concluded the benzene model proposed by Wick et al (2002) was the most suitable for studying adsorption on GTCB. The simulation results for this model on GTCB at 293 K with and without surface mediation are presented in Fig.…”

Section: Surface Mediationmentioning

confidence: 93%

On the physical adsorption of gases on carbon materials from molecular simulation

Birkett

2007

Adsorption

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In this paper we present a series of work covering a range of aspects relating molecular simulation to experiment. The importance of surface mediation type effects to the adsorption of simple and complex gases is demonstrated. Coupled with the adsorption of simple gases is their projection area when used for surface area determination. The pressure dependence of a projection area is demonstrated for argon at 77 and 87.3 K. A simple model is used to account for the degree of graphitisation of a surface is demonstrated and used to account for the isosteric heat behaviour of nongraphitised carbon blacks. Turning from surfaces to porous solids, an alternative treatment of experiment data (either sub or super critical) is presented that avoids the ambiguity of excess amounts adsorbed. Using this method one is able to obtain pore size distributions and amounts adsorbed without relying on such things as helium expansion volumes. Since this type of method is usually applied to composite solids we also demonstrate the correct method for calculating the heat of adsorption using independent sets of simulations. The final topic covered in this paper is an example of the information that can be gained from the heat capacity of an adsorbed phase. Abbreviations a m Molecular projection area nm 2 C V Heat capacity J/mol·K Surface mediation factorg(r) Radial distributionk B Boltzmann's constant J/K k sf Binary interaction parameter -L Length of simulation box nm m p Mass of adsorbent particles in cell kg N A Avogadro's number mol −1 N cell Total amount in adsorption cell mol P Pressure Pa q Partial charge on Coulombs site e Q Heat released J q st Isosteric heat kJ/mol r Separation of interaction sites nm S Particle surface area m 2 /kg V Volume m 3 z 0Distance from surface at zero potential nm ε LJ well depth J σ LJ collision diameter nm ε 0 Permittivity of a vacuum C 2 /J·m ρ s Surface density of carbon atoms nm −2 ρ b Bulk density kmol/m 3 ρ Average pore density kmol/m 3 Δ Carbon layer separation nm χ Surface mediation damping constant -Γ Surface adsorption μmol/m 2 α Volume of specific pore m 3 /kg ϕ Interaction energy J

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Section: Surface Mediationmentioning

confidence: 93%

On the physical adsorption of gases on carbon materials from molecular simulation

Birkett

2007

Adsorption

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“…Model 3 -Extension of the TraPPE force field (Wick et al, 2002). This new representation of the arenes contains a positive partial charge (q center = +2.42 e), placed at the center of the ring, and two negative partial charges representing the π electron clouds (q pi = -1.21 e), placed at a distance of 0.785 Å from the ring center and on a line perpendicular to the arene plane.…”

Section: Methodsmentioning

confidence: 99%

ADSORPTION OF XYLENE ISOMERS IN METAL ORGANIC FRAMEWORK UiO-66 BY MOLECULAR SIMULATIONS

Granato

Martins²,

Ferreira³

et al. 2015

Anais Do XX Congresso Brasileiro De Engenharia Química

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-This work presents results of molecular simulations on adsorption of the four xylene isomers (o-, m-, p-xylene and ethylbenzene) in the porous zirconium terephthalate UiO-66. Grand-canonical Monte Carlo simulations (GCMC) are compared to multi-component adsorption equilibrium data obtained by breakthrough experiments. Additionally, the adsorption behavior of each isomer in order to better understand the multicomponent adsorption was evaluated. The simulations confirm that the experimentally observed ortho-selectivity is preferential in relation to the other isomers. Access to the small cages seems to be favored for o-xylene due to its more compact structure that provides more advantages in terms of rotation degrees of freedom. Furthermore, it was found that there is a competition between the other three isomers for adsorption in the UiO-66.

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“…Benzene was described by the nine-site model of Zhao et al (2005), Wick et al (2002). The partial charges of the zeolite atoms (q o = −1.025e, q si = +2.05e) were taken from Calero et al (2004).…”

Section: Molecular Models and Simulation Methodologymentioning

confidence: 99%

Adsorption of benzene and propene in zeolite MCM-22: a grand canonical Monte Carlo study

Liu

et al. 2011

Adsorption

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The GCMC (grand canonical Monte Carlo) simulation technique was used to predict the competition adsorption characteristics of benzene and propene in different pore systems of MCM-22. The nine-site model of benzene was used, which proved to be effective and efficient. The zeolite was divided into three adsorption sites following a simulated annealing method. It is found that benzene and propene have the same preferential adsorption site and a similar adsorption order in different sites. Moreover, the pure and mixture isotherms of the three sites are drawn. From the isotherms, we obtained a selectivity reversal of the mixture isotherms of benzene and propene in different sites. It is also noted that the competition adsorption in the three adsorption sites for the two adsorbates can fall into three successive steps and the adsorption order of propene in mixture in these three sites is S3 → S1 → S2. A new model is presented to predict the benzene and propene adsorption equilibrium in MCM-22. This approach yields better multicomponent equilibrium predictions than ideal adsorbed solution theory (IAST). Isotherms at different mole fraction of benzene in gas phase indicate an advantage to increase the feed radio of benzene and propene. Thus, this work is helpful for a better understanding of the adsorption mechanism of benzene and propene in MCM-22 and hence the relation of the catalytic properties of the zeolite to its structure.

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Temperature effects on the retention of n-alkanes and arenes in helium–squalane gas–liquid chromatography

Cited by 70 publications

References 34 publications

On the physical adsorption of gases on carbon materials from molecular simulation

On the physical adsorption of gases on carbon materials from molecular simulation

ADSORPTION OF XYLENE ISOMERS IN METAL ORGANIC FRAMEWORK UiO-66 BY MOLECULAR SIMULATIONS

Adsorption of benzene and propene in zeolite MCM-22: a grand canonical Monte Carlo study

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