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zinc-oxide-nanostructures
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Kinetics and Mechanism of the Reduction of Hexavalent Chromium to Less Toxic Materials on ZnO Nanostructured Surfaces: the Effect of Wavelength and Light Intensity on the Reaction Rate
, M.Sc. Thesis Sharif University of Technology ; Moshfegh, Alireza (Supervisor) ; Naseri, Ameneh (Supervisor)
Abstract
Hexavalent chromium ion (Cr+6) is a very toxic type of heavy metal in industrial effluents which is not biodegradable and accumulates in the human body that can cause genetic mutations and cancer. The aim of this project is to investigate the effect of wavelength and intensity of appropriate light on the reaction rate of photocatalytic reduction of Cr+6 ion to less toxic materials. In this project, we first designed and constructed a photocatalytic reactor to investigate the effect of wavelength and intensity of incident light on the reaction rate. The home-made photocatalytic reactor consisted of 120 LEDs in 12 different wavelengths, which has ability to control the intensity and...
Study of Antibacterial Performance of Metal Oxide Nanostructures and their Effect on Bacterial Growth Kinetics
, M.Sc. Thesis Sharif University of Technology ; Naseri, Naimeh (Supervisor) ; Zaker Moshfegh, Alireza (Co-Supervisor)
Abstract
Fighting contagious microbial diseases is considered a serious health issue, which has attracted much attention in worldwide. Thus, development of new materials based on nanostructures as a new generation of antibiotics to address this challenge has been of interest to researchers in recent years. Nanostructures based on metallic oxide semiconductors such as oxides with light absorption, production of electron-hole pairs in needle like structures cause tearing bacterial membrane and eventually destroy the bacterium. To this end, we designed experiments to study mechanism and physics governing the process of bacterial degradation to determine the best conditions for inhibiting bacteria...
Effects of morphology on photocatalytic performance of Zinc oxide nanostructures synthesized by rapid microwave irradiation methods
, Article Superlattices and Microstructures ; Volume 51, Issue 4 , 2012 , Pages 512-522 ; 07496036 (ISSN) ; Ghorbani, H ; Paravar, A ; Samberg, J. P ; Kajbafvala, E ; Sadrnezhaad, S. K ; Sharif University of Technology
2012
Abstract
In this study, two different chemical solution methods were used to synthesize Zinc oxide nanostructures via a simple and fast microwave assisted method. Afterwards, the photocatalytic performances of the produced ZnO powders were investigated using methylene blue (MB) photodegradation with UV lamp irradiation. The obtained ZnO nanostructures showed spherical and flower-like morphologies. The average crystallite size of the flower-like and spherical nanostructures were determined to be about 55 nm and 28 nm, respectively. X-ray diffraction (XRD), scanning electronic microscopy (SEM), Brunauer-Emmett-Teller (BET), room temperature photoluminescence (RT-PL) and UV-vis analysis were used for...
Microwave-assisted synthesis of narcis-like zinc oxide nanostructures
, Article Journal of Alloys and Compounds ; Volume 497, Issue 1-2 , May , 2010 , Pages 325-329 ; 09258388 (ISSN) ; Zanganeh, S ; Kajbafvala, E ; Zargar, H. R ; Bayati, M. R ; Sadrnezhaad, S. K ; Sharif University of Technology
2010
Abstract
Through a fast, simple, low cost, surfactant-free and convenient microwave-assisted route, narcis-like ZnO nanostructures (10-15 nm size) with flower diameters in the range of 1-2.5 μm were synthesized. X-ray diffraction (XRD), scanning electron microscopy (SEM), transmission electron microscopy (TEM), Fourier transform infrared (FTIR) spectroscopy and room temperature photoluminescence (PL) measurements were used to characterize the produced ZnO nanostructures. The principle raw materials - ammonium hydroxide (NH4OH) and zinc acetate dihydrate [Zn(CH3COO)2·2H2O] - were both inexpensive. The method was fast, simple and surfactant-free capable of producing larger quantities of zinc oxide...