Abstract
The molecular mobility of methane and n-hexane adsorbed in X- and A-type zeolites with different calcium contents is studied by pulsed-field gradient (p.f.g.) n.m.r. In contrast to sodium, the calcium ions are found to be of substantial influence on the intracrystalline diffusivities. As a consequence of this interaction, the diffusivities of methane in NaCaA and NaCaX are found to be quite close to each other in both the absolute values and the dependence on temperature and concentration. For n-hexane, the diffusivities in NaCaA are significantly below the diffusivities in NaCaX. This can be attributed to the larger critical diameter of the n-hexane molecules, which is of the order of the diameters of the windows between adjacent supercages in zeolite A. The proposed model of molecular interaction is confirmed by comparison with the results of MD simulations and by n.m.r. tracer desorption measurements with zeolite alpha.
Talk to us
Join us for a 30 min session where you can share your feedback and ask us any queries you have
Schedule a callDisclaimer: All third-party content on this website/platform is and will remain the property of their respective owners and is provided on "as is" basis without any warranties, express or implied. Use of third-party content does not indicate any affiliation, sponsorship with or endorsement by them. Any references to third-party content is to identify the corresponding services and shall be considered fair use under The CopyrightLaw.
