Chromatographic formation of a triadic band of lithium in hydrated LTA zeolite: An investigation on lithium isotope separation effects by ion exchange
| Autor: | Susumu Narita, Akari Takeuchi, Kazuo Yoshino, Hiroshi Ohki, A. Ishikawa, Mie Sasaki |
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| Rok vydání: | 2017 |
| Předmět: |
Hydrated Linde Type A (LTA) zeolite
Isotopes of lithium Inorganic chemistry chemistry.chemical_element 02 engineering and technology 01 natural sciences 010305 fluids & plasmas chemistry.chemical_compound 0103 physical sciences General Materials Science Ammonium Zeolite Chromatography Ion exchange Elution General Chemistry 021001 nanoscience & nanotechnology Condensed Matter Physics Isotopic composition Isotope separation Column experiment chemistry Mechanics of Materials Lithium 0210 nano-technology |
| Zdroj: | Microporous and Mesoporous Materials. 248:115-121 |
| ISSN: | 1387-1811 |
| DOI: | 10.1016/j.micromeso.2017.04.015 |
| Popis: | published online 12 April 2017 Lithium concentrations [Li] and isotopic ratios [Li-7]/[Li-6] were measured for effluent fractions from a biphasic zeolite column. The biphasic state was ascribed to a mixture of hydrated Linde Type A (LTA) zeolites, [Li-0.008(NH4)(0.92)]A and [Li-0.33(NH4)(0.67)]A, which were formed by Li ion exchange from hydrated ammonium in the form (NH4)(12)[Al12Si12O48]center dot nH(2)O (NH(4)A). The biphasic Li band of the column was displaced by ion exchange with a solution of NH4NO3. A constant [Li] with a much lower level than the concentration of NHt(4)(_)(+) in the displacer (NH4NO3) was observed for the effluent from a short column. This constant lower level of [Li] was attributable to the biphasic state. On this [Li] plateau of the effluent, the level of [Li-7] shifted higher than the original isotopic composition of the Li feed, whereas Li-6 was concentrated on the biphasic zeolite solid. The accumulation of Li-6 in the zeolite proceeded by a mechanism of differential elution of Li-7 from the biphasic zeolite. For the long column experiment, a significant enrichment of Li-6 in the zeolite was observed, whereby a triadic band of Li was probably formed in the column. Two monophasic and a biphasic state were assigned. The biphasic band was deemed to push the monophasic bands forward, thereby enriching the monophasic bands with Li-7, while Li-6 accumulated at the end of the biphasic band. The trio structure of the Li band and isotopic discrimination in the band were analyzed. (C) 2017 Elsevier Inc. All rights reserved. Article MICROPOROUS AND MESOPOROUS MATERIALS. 248:115-121 (2017) |
| Databáze: | OpenAIRE |
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