Capillary condensation in heterogeneous mesoporous networks consisting of variable connectivity and pore-size correlation

Abstract

1) constructed under the premises of the dual sitebond model have been used as probe substrates to study the effects of variable connectivity and pore-size correlation on the aspects of both hysteresis loops and primary sorption scanning curves. The shapes of the hysteresis loops obtained from sorption simulation in networks of diverse morphologies are compared and discussed. It is found that the precursor structural parameters of the Monte Carlo simulated networks together with the sorption algorithm used in this work, can lead to IUPAC types H1, H2 and H3-like hysteresis loops, depending on the values chosen for the pore-size distribution parameters and mean connectivity. Network morphology also influences greatly the mechanisms of sorption processes in poorly or highly size correlated porous substrates. Sorption results on these 3-D porous specimens help to visualize the extents of pore blocking (vapour percolation) and delayed adsorption (liquid percolation) phenomena and also to foresee the most appropriate methods to ascertain the structure of porous materials.

Tailoring Porosity of Colloidal Boehmite Sol by Controlling Crystallite Size

“…30,31 In the case of irregular porous materials such as boehmite particles, that is, throats in front of cavities must be filled with N 2 through the capillary condensation so that sites in unsaturated states exist with avoiding the propagation of assisted pore filling. During desorption process, filled N 2 molecules in throats act as stoppers so that a pore-blocking phenomenon takes place, which generates a sudden desorption at a capillary evaporation threshold.…”

Synthesis and Characterization of Ordered Mesoporous Silica Pillared Clay with HPW Heteropoly Acid Encapsulated into the Framework and Its Catalytic Performance for Deep Oxidative Desulfurization of Fuels

“…All samples presented type IV isotherm patterns with H3-type hysteresis loop starting at about 0.4 partial pressure, which are the characteristics of the mesoporous materials with the cylindrical pores formed in gallery regions [52]. For the 25%HPW-SPC-SG sample, the hysteresis loop of the isotherm was obviously smaller than that of the samples with relatively low HPW contents.…”

Systematic Simulation of Disordered Cylindrical Nanoporous Materials

“…In order to demonstrate their potentialities, we have applied them to the sorption of nitrogen at 77 K. We used a simple algorithm based on previous papers to simulate sorption processes [see Rojas et al (2002)]. It is important to note that this procedure is based on determining the limit of stability of the adsorbed phase at each site or bond by means of the Broekhoff-de Boer equation (Broekhoff and de Boer 1967a-d).…”