Effects of Pore–Pore Correlations on Capillary Condensation in an Ensemble of Slit-like Pores: Application of a Density Functional Theory

Patrykiejew, A.; Reszko-Zygmunt, Joanna; Rżysko, W.; Sokołowski, S.

doi:10.1006/jcis.2000.6943

Cited by 4 publications

(5 citation statements)

References 17 publications

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“…As in the case of the smaller pore size, the overall isotherm is only marginally affected with a very small increase in density at high pressures. From these results it would appear that for nitrogen the effect of pore−pore interactions is significant only at small wall thicknesses (single layer walls) and at small pore size, consistent with the observation of Patrikiejew et al . In actual carbons with a randomly distributed wall thickness, the resulting effect of the interactions on the overall isotherm appears to be small and may be neglected in comparison to the effect of the disorder itself.…”

Section: Resultssupporting

confidence: 88%

“…From these results it would appear that for nitrogen the effect of porepore interactions is significant only at small wall thicknesses (single layer walls) and at small pore size, consistent with the observation of Patrikiejew et al. 35 In actual carbons with a randomly distributed wall thickness, the resulting effect of the interactions on the overall isotherm appears to be small and may be neglected in comparison to the effect of the disorder itself. Figure 10 depicts the results obtained as above for butane, for the structures of uniform pore size H* ) 2 and H* ) 3.…”

Section: Resultssupporting

confidence: 87%

“…The above formulation of the model including interactions considers only the effect of adjacent pores, which is sufficient, as fluid-fluid interactions have influence only over a few molecular diameters. In a recent study, Patrikiejew et al 35 have also considered such interactions, but rather than using our mean field approach for the structure, they examine particular configurations of wall thicknesses with the periodicity of the lattice. The present formulation considers all possible configurations with wall thickness probabilities following eq 11, and it is therefore well-suited for determining the adsorption in the entire structure.…”

Section: Resultsmentioning

confidence: 99%

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Density Functional Theory Analysis of the Influence of Pore Wall Heterogeneity on Adsorption in Carbons

Bhatia

2002

Langmuir

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Density functional theory for adsorption in carbons is adapted here to incorporate a random distribution of pore wall thickness in the solid, and it is shown that the mean pore wall thickness is intimately related to the pore size distribution characteristics. For typical carbons the pore walls are estimated to comprise only about two graphene layers, and application of the modified density functional theory approach shows that the commonly used assumption of infinitely thick walls can severely affect the results for adsorption in small pores under both supercritical and subcritical conditions. Under supercritical conditions the Henry's law coefficient is overpredicted by as much as a factor of 2, while under subcritical conditions pore wall heterogeneity appears to modify transitions in small pores into a sequence of smaller ones corresponding to pores with different wall thicknesses. The results suggest the need to improve current pore size distrubution analysis methods to allow for pore wall heterogeneity. The density functional theory is further extended here to allow for interpore adsorbate interactions, and it appears that these interaction are negligible for small molecules such as nitrogen but significant for more strongly interacting heavier molecules such as butane, for which the traditional independent pore model may not be adequate.

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Section: Resultssupporting

confidence: 88%

Section: Resultssupporting

confidence: 87%

Section: Resultsmentioning

confidence: 99%

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Density Functional Theory Analysis of the Influence of Pore Wall Heterogeneity on Adsorption in Carbons

Bhatia

2002

Langmuir

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“…Our explicit model appropriated to investigate interpore interactions was based in the study of Patrykiejew et al (2000). They test a periodic network of pores with width H cc and distance between neighboring pore wall of j .…”

Section: Interpore Adsorbate Interactionsmentioning

confidence: 99%

Pore wall thickness and interpore influence on adsorption of alkanes in carbons using explicit pore models

et al. 2012

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In modeling of activated carbons, the pores are often assumed to be slit-shaped formed of a constant number of graphene layers. X-ray diffraction studies show that micropores are formed between stacks of different numbers of graphene layers. In this study, we investigate, through the grand canonical Monte Carlo method, the influence on the adsorbed alkanes densities of pore walls with different graphene layers thickness and the related interpore adsorbate interaction when the pore wall has only one graphene layer. All studies of thickness and interpore interaction to date were performed using the Steele 10-4-3 potential model. Instead of Steele model, we propose explicit models made up of graphene layers of discrete carbon atoms. We also investigated the sensitivity of the system to the cut-off and solid-fluid parameter. With our explicit model we found that the influence of the number of carbon layers is not significant for n > 2 as previously observed by Steele model-DFT studies. The system was also insensitive to cut-off and well deep parameter variations. A new pore model with an extra dummy graphene wall was proposed to investigate the interpore interaction. The interpore interaction study with the alkanes series C1 to C4 shows that the retention capacity of heavier alkanes is the same whether for activated carbons with few layers (stronger interpore interaction) as for carbons with two or more layers (stronger solid-fluid interaction) assuming negligible surface mediation. The explicit models proposed can be successfully used in the elaboration of virtual porous carbon models to reproduce wall thickness and interpore adsorbate interactions phenomena.

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“…La adsorción se ha estudiado bastante, tanto experimental [85] como teóricamente, mediante la simulación molecular [86][87][88][89][90], métodos de Monte Carlo [91,92], teoría de los funcionales de la densidad [93][94][95] y el DSBM [96][97][98]. La adsorción ocurre porque existe un equilibrio dinámico entre el gas o vapor y la superficie del sólido con el cual está en contacto [77].…”

Section: Sorcion De Nitrógenounclassified

Estudio de fenómenos capilares en medios porosos: sorción de nitrógeno y porosimetría de mercurio. Acuerdos y discordancias

Mendoza

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Effects of Pore–Pore Correlations on Capillary Condensation in an Ensemble of Slit-like Pores: Application of a Density Functional Theory

Cited by 4 publications

References 17 publications

Density Functional Theory Analysis of the Influence of Pore Wall Heterogeneity on Adsorption in Carbons

Density Functional Theory Analysis of the Influence of Pore Wall Heterogeneity on Adsorption in Carbons

Pore wall thickness and interpore influence on adsorption of alkanes in carbons using explicit pore models

Estudio de fenómenos capilares en medios porosos: sorción de nitrógeno y porosimetría de mercurio. Acuerdos y discordancias

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