Variation in the Parameters of the Crystalline Structure of Zeolites during Adsorption

Sarakhov, A. I.; Kononyuk, V. F.; Dubinin, M. M.

doi:10.1021/ba-1973-0121.ch036

Cited by 11 publications

(7 citation statements)

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“…Initial volume increase reflects the onset of repulsions between adsorbate molecules, while the steep increase which follows reflects the complete filling of the zeolite free volume and the elastic response of the framework. A similar trend for the cell volume during physisorption has been observed experimentally by Sarakhov et al 47 in a dilatometric study on the variation in the cell parameters of A, X and Y zeolites during carbon dioxide adsorption. It has also been predicted theoretically by van den Berg et al 21 for dihydrogen adsorption on sodalite frameworks of different compositions.…”

Section: Resultssupporting

confidence: 86%

Theoretical maximal storage of hydrogen in zeolitic frameworks

Vitillo

Ricchiardi

Spoto

et al. 2005

Phys. Chem. Chem. Phys.

108

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Physisorption and encapsulation of molecular hydrogen in tailored microporous materials are two of the options for hydrogen storage. Among these materials, zeolites have been widely investigated. In these materials, the attained storage capacities vary widely with structure and composition, leading to the expectation that materials with improved binding sites, together with lighter frameworks, may represent efficient storage materials. In this work, we address the problem of the determination of the maximum amount of molecular hydrogen which could, in principle, be stored in a given zeolitic framework, as limited by the size, structure and flexibility of its pore system. To this end, the progressive filling with H2 of 12 purely siliceous models of common zeolite frameworks has been simulated by means of classical molecular mechanics. By monitoring the variation of cell parameters upon progressive filling of the pores, conclusions are drawn regarding the maximum storage capacity of each framework and, more generally, on framework flexibility. The flexible non-pentasils RHO, FAU, KFI, LTA and CHA display the highest maximal capacities, ranging between 2.86-2.65 mass%, well below the targets set for automotive applications but still in an interesting range. The predicted maximal storage capacities correlate well with experimental results obtained at low temperature. The technique is easily extendable to any other microporous structure, and it can provide a method for the screening of hypothetical new materials for hydrogen storage applications.

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Section: Resultssupporting

confidence: 86%

Theoretical maximal storage of hydrogen in zeolitic frameworks

Vitillo

Ricchiardi

Spoto

et al. 2005

Phys. Chem. Chem. Phys.

108

View full text Add to dashboard Cite

show abstract

“…2. The maximum contraction was 0.22 vol%, which is consistent with XRD results by Sarakhov et al [17]; they reported that the NaA unit cell contracted as much as 0.3 vol% upon adsorption of low water loadings at room temperature. Correspondingly, during permeation measurements at 303 K, low water activities increased the helium flux through membranes A and B by an average of 80%, as shown in Fig.…”

Section: Water Adsorption At 300 Ksupporting

confidence: 90%

“…This expansion is similar to that measured by XRD in previous studies at high water loading. Barrer and Meier reported that the NaA unit cell expanded 0.49 vol% at 298 K [16], and Sarakhov et al reported a 0.57 vol% expansion at 295 K [17]. The normalized i-butane flux for membrane A (Fig.…”

Section: Water Adsorption At 300 Kmentioning

confidence: 91%

“…Expansion of the LTA unit cell by water has been reported [15][16][17]. Barrer et al [16] reported that the NaA unit cell expanded 0.49 vol% at 298 K when saturated with water [16].…”

Section: Introductionmentioning

confidence: 99%

“…Barrer et al [16] reported that the NaA unit cell expanded 0.49 vol% at 298 K when saturated with water [16]. Sarakhov et al [17] reported that the NaA unit cell contracted as much as 0.3 vol% at 295 K upon adsorption of low loadings of water and expanded 0.57 vol% at saturation water loadings [17]. However, previous studies did not suggest that crystal expansion influenced water/alcohol separation selectivities in NaA membranes.…”

Section: Introductionmentioning

confidence: 99%

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