Crystal-chemical studies of cation-exchanged zeolite A
|Other Titles:||Kristallchemische Untersuchungen an kationenausgetauschten Zeolith A||Authors:||Wang, Li||Supervisor:||Fischer, Reinhard X.||1. Expert:||Fischer, Reinhard X.||2. Expert:||Buhl, Josef-Christian||Abstract:||
Powder and single crystals of K and NH4 exchanged zeolite A were prepared by static exchange methods. The crystal structure of hydrated zeolite K,Na-A and NH4-A were investigated by X-ray diffraction methods (space group Fm-3c) at ambient temperature. The refinement results indicated that all cations and large proportion of water molecules were located in the big grc units. The residual water molecules resided on the 6-fold axes in the toc units. In zeolite NH4-A, dealumination process occurred when the crystal stored in air. The thermal behavior of zeolite K-A, NH4-A and intermediate samples were studied by means of in situ X-ray powder diffraction combined with thermal gravimetric analyses in air and under vacuum conditions. Heavy atoms (Ba2 and Sr2 ) exchanged zeolite A were prepared. The results showed that the low X-ray intensity compared with zeolite Na-A was due to the high absorption coefficient of heavy atoms for X-rays.
|Keywords:||dealumination, thermal behavior, single crystal||Issue Date:||6-Sep-2016||URN:||urn:nbn:de:gbv:46-00105484-15||Institution:||Universität Bremen||Faculty:||FB5 Geowissenschaften|
|Appears in Collections:||Dissertationen|
checked on Sep 19, 2020
Items in Media are protected by copyright, with all rights reserved, unless otherwise indicated.