Syntheses and characterization of phosphated and sulfated zirconium-pillared microporous saponites /
Pillared saponites were prepared by the exchange reactions of
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| Format: | Thesis Book |
| Language: | English |
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[Place of publication not identified] :
[publisher not identified] ;
1996.
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| Subjects: | |
| Online Access: | http://proxy.library.tamu.edu/login?url=http://proquest.umi.com/pqdweb?did=739364091&sid=1&Fmt=2&clientId=2945&RQT=309&VName=PQD |
| Summary: | Pillared saponites were prepared by the exchange reactions of Na-saponite with hydroxy aluminum Keggin ion [AI1304(OH)24(H20)12]7+ and tetrameric hydroxy cations [Zr(OH)2-4(H20)14 8+ under different synthetic conditions. These products were characterized by 27AI NMR, 29Si NMR, thermal stability studies, X-ray diffraction, acid or base treatment, ion exchange capacity, and surface area determination. Zr-pillared saponites with the largest basal spacings (near 25.2 A), that are stable to 800 'C, have surface areas of the order of 300 - 350 m2/g when calcined to 550 'C. Al-pillared saponites with basal spacings near 19 A are stable to 750 'C and exhibit surface areas of 328 m2/g after being calcined to 550 'C. The high surface area is caused by the porosity formed from the spacing of the stable aluminum oxide and zirconium oxide "Pillars" between the layers. The ion exchange capacity is slightly different for sodium, potassium, and cesium ions in these two types of pillared clays. In order to increase the acidity of the pillared saponites, phosphate and sulfate modified zirconium pillared saponites have been synthesized, and their properties were identified by 31P NMR spectra, X-ray diffraction patterns, and pyridine adsorption and desorption experiments. The results are discussed in terms of the suitability of the proposed synthetic methods to obtain the desired properties of the pillared materials. |
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| Item Description: | Vita. "Major Subject: Chemistry". |
| Physical Description: | xx, 184 leaves : illustrations ; 28 cm. Issued also on microfiche from University Microfilms Inc. |
| Bibliography: | Includes bibliographical references: pages 171-179. |