title: Adsorption of n-pentane on mesoporous silica and adsorbent deformation.
abstract: Development of quantitative theory of adsorption-induced deformation is important, e.g., for enhanced coalbed methane recovery by CO2 injection. It is also promising for the interpretation of experimental measurements of elastic properties of porous solids. We study deformation of mesoporous silica by n-pentane adsorption. The shape of experimental strain isotherms for this system differs from the shape predicted by thermodynamic theory of adsorption-induced deformation. We show that this difference can be attributed to the difference of disjoining pressure isotherm, responsible for the solid-fluid interactions. We suggest the disjoining pressure isotherm suitable for n-pentane adsorption on silica and derive the parameters for this isotherm from experimental data of n-pentane adsorption on nonporous silica. We use this isotherm in the formalism of macroscopic theory of adsorption-induced deformation of mesoporous materials, thus extending this theory for the case of weak solid-fluid interactions. We employ the extended theory to calculate solvation pressure and strain isotherms for SBA-15 and MCM-41 silica and compare it with experimental data obtained from small-angle X-ray scattering. Theoretical predictions for MCM-41 are in good agreement with the experiment, but for SBA-15 they are only qualitative. This deviation suggests that the elastic modulus of SBA-15 may change during pore filling.
authors.affiliation: Department of Civil and Environmental Engineering, Princeton University, Princeton, New Jersey 08544, USA. ggor@princeton.edu
authors.forename: Gennady Yu
authors.initials: GY
authors.lastname: Gor
authors.forename: Oskar
authors.initials: O
authors.lastname: Paris
authors.forename: Johannes
authors.initials: J
authors.lastname: Prass
authors.forename: Patrícia A
authors.initials: PA
authors.lastname: Russo
authors.forename: M Manuela L
authors.initials: MM
authors.lastname: Ribeiro Carrott
authors.forename: Alexander V
authors.initials: AV
authors.lastname: Neimark
mesh_terms: D000327:Adsorption; D010316:Particle Size; D010420:Pentanes / Q000737:chemistry*; D016062:Porosity; D012822:Silicon Dioxide / Q000737:chemistry*; D013499:Surface Properties; D013816:Thermodynamics
chemical_list: D010420:Pentanes; C033353:pentane; D012822:Silicon Dioxide