Development of a continuous microwave reactor for the production of zinc oxide

This study involves experimental design and development of continuous microwave reactor for the production of zinc oxide (ZnO) nanoparticles. The reactor consisted of a modified household microwave oven which was operated with a frequency of 2.45 GHz and a maximum output power of 800 W. The modified...

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Main Author:	Razali, Ili Rabihah
Format:	Thesis
Language:	English
Published:	2015
Subjects:	QD Chemistry
Online Access:	http://eprints.utm.my/id/eprint/53779/1/IliRabihahRazaliMFS2015.pdf
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id	my-utm-ep.53779
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spelling	my-utm-ep.537792020-09-02T06:10:35Z Development of a continuous microwave reactor for the production of zinc oxide 2015-05 Razali, Ili Rabihah QD Chemistry This study involves experimental design and development of continuous microwave reactor for the production of zinc oxide (ZnO) nanoparticles. The reactor consisted of a modified household microwave oven which was operated with a frequency of 2.45 GHz and a maximum output power of 800 W. The modified microwave reactor was equipped with two peristaltic pumps and connected to glass columns via T-junction to allow for mixing of the reactants, zinc nitrate hexahydrate (Zn(NO3)2.6H2O) and sodium hydroxide (NaOH), in the microwave system. The effect of process parameters such as retention time, microwave power and reactant concentration on the phase composition, particle morphology and optical properties of ZnO was investigated. At a fixed concentration of the reactants, crystalline phase of ZnO was formed as observed from the X-ray Diffraction (XRD) patterns. Also, the phase crystallinity of ZnO was found to improve when the retention time of the reactants in the reactor was increased up to 20 min and increasing of the microwave power until 600 W. Besides, increasing the concentration of reactants has successfully produced crystalline phase pure ZnO nanoparticles which were obtained using the mole ratio of Zn(NO3)2.6H2O:NaOH of 1:2. Transmission Electron Microscopy (TEM) image revealed spherical-shape ZnO nanoparticles with sizes ranging from 6 to 12 nm and the result matched well with the crystallite sizes determined from the XRD data using the Scherrer equation. The ZnO nanoparticles exhibited a strong absorption in the 390 nm region of the Ultraviolet-Visible (UV-Vis) spectra which is red-shifted from bulk ZnO (370 nm) with the band-gap value of 3.15 eV. The peak intensity was increasingly decreased along with increasing of retention time, microwave power and reactant concentration while the band-gap energies were found to decrease upon increasing of the retention time, microwave power and reactant concentration. The green band emission observed in the region of 350-470 nm in the Photoluminescence (PL) spectra suggests the presence of high oxygen vacancies in the ZnO lattice which then further reduced with increasing of retention time, microwave power and reactant concentration. 2015-05 Thesis http://eprints.utm.my/id/eprint/53779/ http://eprints.utm.my/id/eprint/53779/1/IliRabihahRazaliMFS2015.pdf application/pdf en public http://dms.library.utm.my:8080/vital/access/manager/Repository/vital:85424 masters Universiti Teknologi Malaysia, Faculty of Science Faculty of Science
institution	Universiti Teknologi Malaysia
collection	UTM Institutional Repository
language	English
topic	QD Chemistry
spellingShingle	QD Chemistry Razali, Ili Rabihah Development of a continuous microwave reactor for the production of zinc oxide
description	This study involves experimental design and development of continuous microwave reactor for the production of zinc oxide (ZnO) nanoparticles. The reactor consisted of a modified household microwave oven which was operated with a frequency of 2.45 GHz and a maximum output power of 800 W. The modified microwave reactor was equipped with two peristaltic pumps and connected to glass columns via T-junction to allow for mixing of the reactants, zinc nitrate hexahydrate (Zn(NO3)2.6H2O) and sodium hydroxide (NaOH), in the microwave system. The effect of process parameters such as retention time, microwave power and reactant concentration on the phase composition, particle morphology and optical properties of ZnO was investigated. At a fixed concentration of the reactants, crystalline phase of ZnO was formed as observed from the X-ray Diffraction (XRD) patterns. Also, the phase crystallinity of ZnO was found to improve when the retention time of the reactants in the reactor was increased up to 20 min and increasing of the microwave power until 600 W. Besides, increasing the concentration of reactants has successfully produced crystalline phase pure ZnO nanoparticles which were obtained using the mole ratio of Zn(NO3)2.6H2O:NaOH of 1:2. Transmission Electron Microscopy (TEM) image revealed spherical-shape ZnO nanoparticles with sizes ranging from 6 to 12 nm and the result matched well with the crystallite sizes determined from the XRD data using the Scherrer equation. The ZnO nanoparticles exhibited a strong absorption in the 390 nm region of the Ultraviolet-Visible (UV-Vis) spectra which is red-shifted from bulk ZnO (370 nm) with the band-gap value of 3.15 eV. The peak intensity was increasingly decreased along with increasing of retention time, microwave power and reactant concentration while the band-gap energies were found to decrease upon increasing of the retention time, microwave power and reactant concentration. The green band emission observed in the region of 350-470 nm in the Photoluminescence (PL) spectra suggests the presence of high oxygen vacancies in the ZnO lattice which then further reduced with increasing of retention time, microwave power and reactant concentration.
format	Thesis
qualification_level	Master's degree
author	Razali, Ili Rabihah
author_facet	Razali, Ili Rabihah
author_sort	Razali, Ili Rabihah
title	Development of a continuous microwave reactor for the production of zinc oxide
title_short	Development of a continuous microwave reactor for the production of zinc oxide
title_full	Development of a continuous microwave reactor for the production of zinc oxide
title_fullStr	Development of a continuous microwave reactor for the production of zinc oxide
title_full_unstemmed	Development of a continuous microwave reactor for the production of zinc oxide
title_sort	development of a continuous microwave reactor for the production of zinc oxide
granting_institution	Universiti Teknologi Malaysia, Faculty of Science
granting_department	Faculty of Science
publishDate	2015
url	http://eprints.utm.my/id/eprint/53779/1/IliRabihahRazaliMFS2015.pdf
_version_	1747817625314918400

Development of a continuous microwave reactor for the production of zinc oxide

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