Adsorption Properties Of The In Situ Synthesized Granulated Faujasites
ADSORPTION PROPERTIES OF THE IN SITU SYNTHESIZED GRANULATED FAUJASITES
K. Patrylak1, P. Bartosh1, A. Yakovenko1,
R. Leboda2, J. Skubiszewska-Zięba2
1Institute of Bioorganic Chemistry and Petrochemistry of National Academy of Sciences of Ukraine; 1, Murmans’ka vul., Kyiv, 02094 Ukraine
2Department of Chemical Physics, Faculty of Chemistry,
Maria Curie-Sklodowska University; 20031 Lublin, Poland
There are two main industrial methods of the preparation of zeolites and zeolite catalysts: the mixing method, when the pure zeolite is mixed with the matrix components, and in situ one, when the zeolite is synthesized in a previously formed matrix material, for example in kaolin granules. The second method is especially attractive for Ukraine in few of its great deposits of high quality kaolins. Besides, zeolite component of the adsorbents and catalysts, synthesized in situ, is notable for heightened thermal stability due to the genetic bonding of the part of matrix material with the zeolite phase [1].
The present work aims to obtain the Y-zeolite-containing granulated samples and to evaluate their adsorption characteristics against the characteristics of industrial granulated zeolite.
The parent kaolin powder (Prosyana deposit, Ukraine), kaolin calcined at 1000 oC for 2 h to spinel, as well as metakaolin microspheres (50-100 mcm) in ratio 1:1:1 were mixed carefully. After the dropwise addition of aqueous solution of Na2SiO3 to obtain the doughy mass of the proper standard, the last was extrude to the granules of 4 mm in diameter and 6-8 m in length. Granules were dried at 100-120 oC for 24 h and then calcined at 740 oC for 2 h to transform the kaolin into metakaolin and to strengthen the granules. The further in situ synthetic procedure was, on the whole, alike to the produce using for the obtainment of zeolite-containing microsphere [2].
The adsorption characteristics were recorded by means of low temperature (77.4 K) nitrogen adsorption method.
The results obtained (Table) show, on the whole, a proximity of the main characteristics of samples 1 and 3. Some advantages of synthesized sample
show characteristics 1-5, 8 which concern chiefly the microporosity, whereas in meso- and macroporosity (positions 6, 7, 9-11) some advantages belong to the industrial sample. Sample 2 is superior to samples 1 and 3.
Table. Adsorption Characteristics of Zeolite-Containing Granules and an Industrial Adsorbent
No.
Characteristic and its dimension
Sample
1
2
Industrial Sample
1
BET surface area, m2/g
314
463
299.8
2
Langmuir surface area, m2/g
389.9
575
372
3
BJH cumulative adsorption surface area of pores between 17 and 3000 Ǻ diameter, m2/g
24.8
64.7
23.4
4
BJH cumulative desorption surface area of pores between 17 and 3000 Ǻ diameter, m2/g
33.4
81.2
28.6
5
Micropore area, m2/g
284.1
399.9
269.5
6
BJH cumulative adsorption pore volume of pores between 17 and 3000 Ǻ diameter, cm3/g
0.039
0.117
0.065
7
BJH cumulative desorption pore volume of pores between 17 and 3000 Ǻ diameter, cm3/g
0.044
0.125
0.071
8
Micropore volume, cm3/g
0.125
0.176
0.119
9
Average pore diameter, Ǻ
17
20
19
10
BJH adsorption average diameter, Ǻ
62
72
110
11
BJH desorption average diameter, Ǻ
53
61
99
Thus, it seems to be possible to prepare the granulated Y zeolite of high thermal stability, its adsorption properties being comparable with those of the industrial sample.
References
1. Patrylak L.K., Likhnyovskyi R.V., Kukushkina A.V., Bartosh P.I., Vypyrailenko V.Yo., Patrylak K.I. Ukr. Chem. J., 66 (2), 36 (2000).
2. Patrylak L. Adsorpt. Sci. Technolog., 18 (5), (2000).
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