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Adsorption behavior of N-2 water, C-6 hydrocarbons, and bulkier benzene derivative (TMB) on Na-X zeolite and its K+-, Rb+-, and Cs+-exchanged analogues

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Title Adsorption behavior of N-2 water, C-6 hydrocarbons, and bulkier benzene derivative (TMB) on Na-X zeolite and its K+-, Rb+-, and Cs+-exchanged analogues
 
Creator Joshi, UD
Joshi, PN
Tamhankar, SS
Joshi, VV
Shiralkar, VP
 
Subject Chemistry, Physical
 
Description The hydrothermal crystallization of X-type zeolite with a Si/Al ratio of 1.15 was achieved from the Na2O-Al2O3-SiO2-H2O system at 368 K under static conditions. The post-synthesis modification was carried out by a conventional ion-exchange technique to obtain K+-, Rb+-, and Cs+-exchanged samples with different degrees of exchange. All the samples were characterized using chemical analysis, IR, SEM, powder XRD, low-temperature nitrogen adsorption, and equilibrium sorption uptakes of different probe molecules. The relative intensities of the XRD peaks of cation-exchanged zeolite were found to be affected to different extents, depending on the nature and the concentration of nonframework cationic size, without any shift in the positions of reflection. The sorptive properties of the K-, Rb-, and Cs-exchanged samples were studied using nitrogen, water, and different C-6 hydrocarbons including bulkier benzene derivative 1,3,5-trimethylbenzene (TMB) as probe molecules. The trend observed in chemical potential estimated as a function of nitrogen coverage indicates different sorption selectivity because of differences in the cationic size and population. Sorption uptake kinetics for probe molecules such as water, n-hexane, cyclohexane, benzene, and TMB were also studied. The samples with higher degrees of exchange and/or cationic size have shown a decrease in hydrophilic character due to the formation of irregular networks of water molecules connected with preadsorbed water molecules, framework oxygen ions, and nonframework cations. Among Cg hydrocarbons including TMB, the benzene molecule is found to be the most promising probe for the estimation of openness of structure and surface heterogeneity as well. (C) 2001 Academic Press.
 
Publisher ACADEMIC PRESS INCSAN DIEGO525 B ST, STE 1900, SAN DIEGO, CA 92101-4495 USA
 
Date 2011-09-24T09:11:42Z
2011-09-24T09:11:42Z
2001
 
Type Article
 
Identifier JOURNAL OF COLLOID AND INTERFACE SCIENCE
0021-9797
http://hdl.handle.net/123456789/24127
 
Language English