Use this URL to cite or link to this record in EThOS: http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.729253
Title: Syntheses & characterization of nanoZSM-5 & MOR zeolites, characterization of ZNS in the pore network of MOR
Author: Afridi, Pirzada
ISNI:       0000 0004 6493 7900
Awarding Body: University of Oxford
Current Institution: University of Oxford
Date of Award: 2017
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Abstract:
This study was carried out on the synthesis of mordenite zeolite and ZSM-5 zeolite. In Chapter 3 reports the growth of ZnS nanoclusters in the pore channels of mordenite zeolite. ZnS as an important wide-band-gap (3.6 eV) semiconductor nanoclusters and have various technological applications such as photocatalysis, nonlinear optics, sensors, solar cells, injection lasers, flat panel displays, ultraviolet light emitting diodes (LED). Zeolites have several different applications in industries, such as in catalysis, ion exchange adsorption and gas separation. Zeolites are mostly used as a catalyst in the petrochemical industry. ZSM-5 zeolite is widely used a heterogeneous catalyst in the petrochemical industry due to its unique porous structure. Special attention has been made to synthesize nano-ZSM-5 in order to improve its catalytic activity. Catalysis depends on the characteristics length scale of the active sites, while the rate depends on the accessible active sites. In order to improve the performance of ZSM-5 zeolite used as a catalyst in the petrochemical industry, the researchers amid to produce nanocrystalline of the ZSM-5 zeolite. That will help to reduce the path length for the reaction and hence will increase the rate of a reaction. Comparative synthesis nano-particles of ZSM-5 zeolite using two different methods of treatment i.e. pre-treatment and interrupted treatment with ultrasound and without ultrasound was studied, its effect on aging and crystal growth during the hydrothermal treatment. In Chapter 4 the pre-treatment with ultrasound and without ultrasound (static) with an increasing time intervals have been reported. The resulting product the particle size is clearly decreased by using ultrasound pre-treatment. While in Chapter 5 using a different method of treatment called interrupted of the hydrothermal process. As in this method, we stopped the hydrothermal process for 20 minutes and treated the gel with ultrasound for 15 minutes. This treatment was repeated after every 2 hours of hydrothermal treatment. Similarly, the same method was applied to the experiment but without the use of ultrasound called a static method of aging. A 3rd method was also applied to investigate the effect of ultrasound on the particle size distribution of the synthesized crystalline powder. All the results showed that the ultrasound not only effects on the particle size but it also affects the crystallinity too i.e. increased the crystallinity and the reduced in the particle size.
Supervisor: Edwards, Peter ; Sartbaeva, Asel Sponsor: Not available
Qualification Name: Thesis (Ph.D.) Qualification Level: Doctoral
EThOS ID: uk.bl.ethos.729253  DOI: Not available
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