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The Synthesis and Characterization of Nano Zeolitic Molecular Sieve for Separation of 133Xe from 85Kr

Charkhi, Amir | 2011

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  1. Type of Document: Ph.D. Dissertation
  2. Language: Farsi
  3. Document No: 41629 (06)
  4. University: Sharif University of Technology
  5. Department: Chemical and Petroleum Engineering
  6. Advisor(s): Kazemeini, Mohammad; Ahmadi, Javad
  7. Abstract:
  8. In this study the feasibility of xenon separation from xenon-krypton mixture was investigated by utilizing of the chromatographic column filled with nano and micron sized NaY zeolite. For this purpose the nano NaY with the yield of 100% related to Al2O3 and the average size of 98.6 nm was synthesized through the clear solution method with the mid-adding of NaOH. Furthermore, a novel method for granulation of nano zeolite was developed by utilizing sodium alginate as an external template. In this method the production of uniform spherical granules with the different sizes in the range of several milimiteres to 100 µm was easily performed. Moreover, the results showed that the adding of bentonite as a binder to these granules in the range of 20 to 40 weight percent caused increase in mechanical strength by 228%, decrease in the BET surface area by 145% and decrease in Sr2+ removal from the aqueous solution by 27%. In addition, by utilizing the first normalized and the second central moment of response peakes in chromatographic method the Henry’s law constant of xenon and krypton over as synthesized nano zeolite at the temperature of 30-1100C was estimated in the range of 10.2-44.2 and 2.3-7.4, respectively. In a similar method the diffusivity of zenon and krypton in the as synthesized nano NaY crystal was measured in the range of 1.36-4 e-5 and 3.89-4 e-5 m2/s, respectively. Furthermore, the heat of adsorption of xenon and krypton on the as synthesized nano NaY was evaluated equal to 17.61 and 13.99 kj/mol. The activation energy of crystal diffusivity of xenon and krypton was also measured equal to 12.68 and 1.07 kj/mol. Moreover the obtained results revealed that the gas adsorption and cation exchange characteristics of granulated nano NaY has been improved in comparison with the granulated commercial micron sized NaY. At the other part of this work the possibility of mechanically production of nano zeolite was investigated by utilizing of ball milling. In order to determine appropriate milling conditions with respect to the final product crystallinity, particle size and distribution, different milling parameters such dry and wet milling durations, rotational speed, balls to powder ratio and water to powder ratio in wet milling was investigated. The results showed that under certain situations optimized in this study the production of nanozeolite by utilizing the planetry ball milling is feasible.

  9. Keywords:
  10. Diffusion Coefficient ; Clinoptilolite ; Milling ; Chromatography ; Nanozeolite ; Crystal Diffusivity ; Henry Law Constant ; Xenon ; Krypton

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