Abstract
High resolution MAS NMR was used to investigate the progressive dehydration of NaX and NaY zeolites and to study the cation distribution in a series of dehydrated partially exchanged (Li, Ca) NaX. The 23Na spectrum of a totally dehydrated NaX exhibits a line at −40ppm which differs from that observed in NaY, demonstrating an influence of the Si/AI ratio. In partially exchanged (Li,Ca)NaX, Li+ and Ca2+ seem to act in opposite ways. Li+ has a tendency to substitute the Na+ in the more constrained sites, leading to narrow 23Na lines, whereas Ca2+ seems to force the remaining Na+ into highly asymmetric environments where it gives broad NMR signals which can only be partially observed. The 7Li NMR signal is quantitatively detected and at least two clearly separated lines are observed in dehydrated samples.
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 callMore From: Proceedings from the Ninth International Zeolite Conference
Disclaimer: 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.
