Behavior of cesium cation in zeolite Y (FAU, Si/Al = 1.56) and their single-crystal structures, |Cs75−xNax|[Si117Al75O384]-FAU (x = 35 and 54)
To study the tendency of Cs + exchange into zeolite Y (Si/Al = 1.56) dependence on Cs + and Na + concentration of aqueous solution during exchange, two single-crystals of fully dehydrated, Cs + -and Na + -exchanged zeolites Y were prepared by the flow method using a mixed ion-exchange solution whose...
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Published in | Journal of porous materials Vol. 24; no. 1; pp. 55 - 64 |
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Main Authors | , , |
Format | Journal Article |
Language | English |
Published |
New York
Springer US
01.02.2017
Springer Nature B.V |
Subjects | |
Online Access | Get full text |
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Summary: | To study the tendency of Cs
+
exchange into zeolite Y (Si/Al = 1.56) dependence on Cs
+
and Na
+
concentration of aqueous solution during exchange, two single-crystals of fully dehydrated, Cs
+
-and Na
+
-exchanged zeolites Y were prepared by the flow method using a mixed ion-exchange solution whose CsNO
3
:NaNO
3
mol ratios were 1:1 (crystal 1) and 1:100 (crystal 2), respectively, with a total concentration of 0.1 M, followed by vacuum dehydration at 723 K. Their crystals were determined by single-crystal synchrotron X-ray diffraction techniques in the cubic space group
Fd
3
¯
m
, respectively, and were refined to the final error indices
R
1
/
wR
2
= 0.084/0.248 and 0.088/0.274 for crystals 1 and 2, respectively. In the structure of |Cs
40
Na
35
|[Si
117
Al
75
O
384
]-FAU (crystal 1), 40 Cs
+
ions per unit cell occupy five different equipoints; 3, 3, 14, 9, and 11 are at sites I, II′, II, IIIa and IIIb, respectively, whereas, the remaining 35 Na
+
ions occupy three different sites: 9, 11, and 15 are at sites I, I′, and II, respectively. In the structure of |Cs
21
Na
54
|[Si
117
Al
75
O
384
]-FAU (crystal 2), 21 Cs
+
ions per unit cell occupy three equipoints; 4, 6, and 11 are at sites II, IIIa, and IIIb, respectively. The residual 54 Na
+
ions per unit cell are found at three different sites; 6, 20 and 28 are at sites I, I′, and II, respectively. The degrees of ion exchange are 53 and 28 % for crystals 1and 2, respectively. This result shows that the degree of Cs
+
exchange decreased sharply by decreasing the initial Cs
+
concentration and increasing the initial Na
+
concentration in given ion-exchange solution. |
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ISSN: | 1380-2224 1573-4854 |
DOI: | 10.1007/s10934-016-0237-5 |