Adsorption and desorption of nitrogen at 77 K on micro- and meso- porous materials: Study of transport kinetics

Zelenka, Tomáš

doi:10.1016/j.micromeso.2016.03.009

Cited by 51 publications

(15 citation statements)

References 44 publications

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“…The magnitude of SSA of Al-rich SROAS and the fact that it is not substantially affected by outgassing evidence that inaccessibility of interparticle spaces to N 2 molecules was caused by freezing and homogeneously distributed within the material since otherwise water emission would have created porosity. Small pore sizes and possibly sorbed water likely restricted N 2 diffusion, an effect that is particularly relevant for pores < 1 nm 77 . Taking this effect into account by assuming a maximal pore radius of 2 nm, calculation of the respective particle diameter that is necessary to explain impermeable aggregate surfaces on the basis of cubic close-packing of monodisperse spheres gives a value of 4.8 nm (see Supplementary information ).…”

Section: Resultsmentioning

confidence: 99%

Synthesis of short-range ordered aluminosilicates at ambient conditions

Lenhardt

Breitzke

Buntkowsky

et al. 2021

Sci Rep

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We report here on structure-related aggregation effects of short-range ordered aluminosilicates (SROAS) that have to be considered in the development of synthesis protocols and may be relevant for the properties of SROAS in the environment. We synthesized SROAS of variable composition by neutralizing aqueous aluminium chloride with sodium orthosilicate at ambient temperature and pressure. We determined elemental composition, visualized morphology by microscopic techniques, and resolved mineral structure by solid-state 29Si and 27Al nuclear magnetic resonance and Fourier-transform infrared spectroscopy. Nitrogen sorption revealed substantial surface loss of Al-rich SROAS that resembled proto-imogolite formed in soils and sediments due to aggregation upon freezing. The effect was less pronounced in Si-rich SROAS, indicating a structure-dependent effect on spatial arrangement of mass at the submicron scale. Cryomilling efficiently fractured aggregates but did not change the magnitude of specific surface area. Since accessibility of surface functional groups is a prerequisite for sequestration of substances, elucidating physical and chemical processes of aggregation as a function of composition and crystallinity may improve our understanding of the reactivity of SROAS in the environment.

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Section: Resultsmentioning

confidence: 99%

Synthesis of short-range ordered aluminosilicates at ambient conditions

Lenhardt

Breitzke

Buntkowsky

et al. 2021

Sci Rep

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“…Isotherms with type H3 hysteresis do not exhibit any limiting adsorption at high p / p 0 . This behavior can, for instance, be caused by the existence of non-rigid aggregates of plate-like particles or assemblages of slit-shaped pores and basically should not be expected to provide a reliable assessment of either the pore size distribution or the total pore volume [32]. …”

Section: Resultsmentioning

confidence: 99%

“…For Samples 5 and 6, the asymmetric region above 0.8 p / p 0 reflects wide (secondary) mesopores with sizes >10 nm that do not necessarily have a significant volume [32]. Samples prepared with a high amount of ODTES shows very different size distribution curves for adsorption and desorption branches.…”

Section: Resultsmentioning

confidence: 99%

Synthesis of Non-Toxic Silica Particles Stabilized by Molecular Complex Oleic-Acid/Sodium Oleate

Spataru

Ianchiş

Petcu

et al. 2016

IJMS

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The present work is focused on the preparation of biocompatible silica particles from sodium silicate, stabilized by a vesicular system containing oleic acid (OLA) and its alkaline salt (OLANa). Silica nanoparticles were generated by the partial neutralization of oleic acid (OLA), with the sodium cation present in the aqueous solutions of sodium silicate. At the molar ratio OLA/Na+ = 2:1, the molar ratio (OLA/OLANa = 1:1) required to form vesicles, in which the carboxyl and carboxylate groups have equal concentrations, was achieved. In order to obtain hydrophobically modified silica particles, octadecyltriethoxysilane (ODTES) was added in a sodium silicate sol–gel mixture at different molar ratios. The interactions between the octadecyl groups from the modified silica and the oleyl chains from the OLA/OLANa stabilizing system were investigated via simultaneous thermogravimetry (TG) and differential scanning calorimetry (DSC) (TG-DSC) analyses.A significant decrease in vaporization enthalpy and an increase in amount of ODTES were observed. Additionally, that the hydrophobic interaction between OLA and ODTES has a strong impact on the hybrids’ final morphology and on their textural characteristics was revealed. The highest hydrodynamic average diameter and the most negative ζ potential were recorded for the hybrid in which the ODTES/sodium silicate molar ratio was 1:5. The obtained mesoporous silica particles, stabilized by the OLA/OLANa vesicular system, may find application as carriers for hydrophobic bioactive molecules.

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“…The works [4][5][6][7] illustrating the current state of the question of the specific surface area analysis of mesoporous materials are presented. Mesoporous materials are widely used in practice (bioengineering, sensorics of gaseous media and environmental monitoring, power engineering, lithium-ion batteries), are used as adsorbents and catalysts for oil refining processes.…”

Section: Introductionmentioning

confidence: 99%

Overview of sorption analysis capabilities for meso- and microporous zeolites nanomaterials

Tokmeilova

Мараева

2021

Chim.Tech.Acta

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In this paper we consider the main application features of the thermal desorption method of inert gases, implemented on the Sorbi MS (Meta, Russia) device, for the analysis of meso- and microporous materials. Recommendations on the choice of measurement modes for stable operation of the Sorbi MS device are offered (including recommendations on mass, sample preparation mode). The article presents the results of the micropores analysis by the t-plot and Sing method.

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Adsorption and desorption of nitrogen at 77 K on micro- and meso- porous materials: Study of transport kinetics

Cited by 51 publications

References 44 publications

Synthesis of short-range ordered aluminosilicates at ambient conditions

Synthesis of short-range ordered aluminosilicates at ambient conditions

Synthesis of Non-Toxic Silica Particles Stabilized by Molecular Complex Oleic-Acid/Sodium Oleate

Overview of sorption analysis capabilities for meso- and microporous zeolites nanomaterials

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