Assessment of Porosities of SBA-15 and MCM-41 Using Water Sorption Calorimetry

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Assessment of Porosities of SBA-15 and MCM-41 Using Water Sorption Calorimetry

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Publication Article, peer reviewed scientific
Title Assessment of Porosities of SBA-15 and MCM-41 Using Water Sorption Calorimetry
Author(s) Kocherbitov, Vitaly ; Alfredsson, Viveka
Date 2011
English abstract
Water sorption calorimetry has been used for characterization of 2D hexagonally ordered mesoporous silica SBA-15. Experimental data on water sorption isotherm, the enthalpy, and the entropy of hydration of SBA-15 are presented. The results were compared with previously published results on MCM-41 obtained using the same technique. The water sorption isotherm of SBA-15 consists of four regimes, while the sorption isotherm of MCM-41 consists only of three. The extra regime in the water sorption isotherm for SBA-15 arises from filling of intrawall pores, that are present in SBA-15 but absent in MCM-41. The water sorption isotherms of the two types of mesoporous silica were analyzed using the Barrett−Joyner−Halenda approach. For the BJH analysis, t-curves of silica with different degrees of hydroxylation were proposed. Comparison of water and nitrogen t-curves shows that, independent of hydroxylation of silica surface, the adsorbed film of water is much thinner than the adsorbed film of nitrogen at similar relative pressures. This fact decreases the uncertainty of the assessment of porosity with water sorption originated from variations in surface properties. The pore size distribution of SBA-15 calculated with BJH treatment of water sorption data is in good agreement with nitrogen NLDFT results on the same material.
DOI http://dx.doi.org/10.1021/la103807v (link to publisher's fulltext)
Publisher American Chemical Society
Host/Issue Langmuir;7
Volume 27
ISSN 0743-7463
Pages 3889-3897
Language eng (iso)
Subject(s) Nanomaterials
SBA-15
water sorption
Sorption calorimetry
Sciences
Research Subject Categories::NATURAL SCIENCES
Handle http://hdl.handle.net/2043/12860 (link to this page)

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