الفهرس 
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Abstract
English Summary
The thesis aims to fabricate some simple metal oxides (ZrO2 and SiO2) and nanocomposites (ZrO2/SiO2) using an auto-combustion method. The simple oxides and nanocomposites have been characterised by using different instruments. The prepared oxides have been applied to degrade crystal violet and methylene blue dyes in aqueous solutions. Various factors affecting degradation of the dyes were studied.
The thesis consists of three main chapters:
Chapter 1: Introduction
The first chapter is an introduction about water pollution, water treatment method, definition of nanomaterials and the fabrication techniques of nanomaterials as well as their applications in different fields. This chapter also includes literature survey on the previous work performed on the simple and mixed metal oxides and their various applications such as water purification.
Chapter 2: Experimental
This chapter includes the description of the materials, reagents, and the methods which were used for the synthesis of simple and composite. Zirconium oxide (ZrO2) nanoparticles were prepared via combustion method using different fuels such as (CTAB, SDS and TW80) after calcination at 500 o C for 15 min. Silicon dioxide (SiO2) nanoparticles were fabricated via combustion method using different fuels such as (CTAB, SDS and TW80) after calcination at 850 o C for 4 h. SiO2/ZrO2 nanocomposites were synthesized from the obtained ZrO2 and SiO2 nonoparticles using ultrasonication process for 15 min. The obtained nanocomposites were then dried at 100 o C for 2 h followed by calcination at 800 oC for 2 h.
This chapter contains the instrumental tools which are used in the characterization of the synthesized simple and composite materials. It includes the description of the method which was used for the removal of dyes from aqueous media.
Chapter 3: Results and discussion
This chapter contain the discussion and results of the extracted results. It can be divided into two main parts.
The first part
The first part describes the characterisation of the obtained simple and mixed metal oxides nanocomposites by different tools such as thermal analysis (TG-DTA), powder X-ray (XRD), infrared spectroscopy (FTIR), scanning electron microscopy (SEM), transmission electron microscopy (TEM), diffuse reflectance spectroscopy (DRS) and UV-Vis spectrophotometer.
The extracted results showed that the obtained zirconium oxide using auto-combustion method in the nanometer range. The crystalline size were determined using X-ray and was ranging (4-8), (5-12) and (8-13) for the ZS, ZT and ZC samples, respectively. The transmission electron microscopy showed that the products have hexagonal and spherical shapes with agglomeration and average particle sizes in the range of 31 nm. FT-IR spectra appeared peaks at 800-1000 cm-1, which related to the zirconium oxide nanoparticles.
Extracted data showed that obtained silicon dioxide using combustion method in the nanometer range. The determined crystalline size using X-ray powder diffraction were found to be (13-16), (5-12) and (7-14) nm for the SS, ST and SC samples, respectively. FT-IR spectra appeared bands at 400-1100 cm-1, which related to the silicon dioxide nanopaticles.
The results showed that ZrO2/SiO2 nanocomposites were synthesized in the nanometer range. XRD results confirmed the presence of the obtained nanocomposites without any impurities, as well as the crystalline size were in the range (5-7.5), (13-14) and (11-26) nm for ZSS, ZST and ZST samples, respectively. The transmission electron microscopy revealed that the particles have hexagonal and spherical shapes as result of the presence a mixture of zirconium and silicon oxides nanoparticles with an average particle size of 58 nm. FT-IR spectra showed the strong absorption bands at 450, 550, 600 and 650 cm−1 for all samples corresponding to Si-O and Zr-O stretching vibration mode of ZrO2 and SiO2 nanoparticles.
The second part
The second part includes the photocatalytic degradation data for the crystal violet and methylene blue dye in aqueous media using the synthesized ZrO2, SiO2 and ZrO2 / SiO2 nanoparticles. This part includes the results and discussion of the factors affecting the degradation of the dye from aqueous solutions such as contact time, dose and effect of H2O2. The optimum conditions for the degradation process were as follows:
1- The contact time for the degradation of crystal violet using the synthesized samples was about 70 min. the degradation of crystal violet decreases with the raise of the dose of the synthesized simple and mixed oxide. The degradation of crystal violet dye over the synthesized sample fitted the pseudo first order model. The degradation of the crystal violet dye increased in the presence of H2O2. Finally, the degradation of crystal violet dye over the fabricated sample and mixed sample.
2- The contact time for the degradation of methylene blue using the synthesized samples takes about 70 min. the degradation of methylene blue decreases with the raise of the dose of the synthesized simple and mixed oxide. The degradation of methylene blue dye over the synthesized sample fitted the pseudo first order model. The degradation of the methylene blue dye increased in the presence of H2O2. Finally, the degradation of methylene blue dye over the fabricated sample and mixed sample.