الفهرس 
Introduction and Objective of workOnly 14 pages are availabe for public view
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Abstract
Organic pollutants come from industrial effluents are very dangerous to human beings, animals and plants directly or indirectly by destroying the healthy environment around them. Consequently, these pollutants must be removed by economic and eco-friendly methods. Chemical, physical and biological methods are used for the removal of these pollutants from water and waste water. Among all chemical methods, heterogeneous photocatalytic oxidation reaction especially based on semiconductor efficient for removal a large number of persistent organic pollutants in both water and waste water. ZnO is considered a promising n-type semiconductor due to its non–toxicity, low cost, appropriate redox potential and physicochemical stability. However, the wide band gap (3.37 eV) limits the photocatalytic activity of ZnO to UV light only (3-5% of solar light). Moreover, the photocorrosion, high rate for recombination rate of the photoinduced charge carriers when subjected to irradiation reduce the optimization of the nanoparticles in photocatalytic process. ZnO exhibits low surface area that reduces the number of radicals generated from its surface.
Summary
In this thesis, a successful destruction of Rhodamine B dye as cationic organic pollutant model was carried out on the surface of novel Ag2CO3/ZnO/SiO2 nanocomposites containing various proportions of Ag2CO3. ZnO nanoparticles were loaded on SiO2 which was extracted from rice straw by sol-gel route . However, Ag2CO3 nanoparticles were incorporated by incipient wetness route . Fourier transform infra-red [FTIR] ,X–ray diffraction [XRD], N2-adsorption-desorption isotherm, diffuse reflectance spectra [DRS] and high-resolution transmission electron microscope [HR-TEM] were carried out to investigate the physicochemical properties of the novel nanocomposites. Homogeneous dispersion of Ag2CO3 nanoparticles of crystallite size (8-19) nm on ZnO/SiO2 of surface area 650 m2/g. Compared with pure ZnO/SiO2, Ag2CO3/ZnO/SiO2 improves the photocatalytic degradation of rhodamine B dye in the visible region, and the photo reactivity increases with increasing Ag2CO3 up to 15 wt%. Kinetic studies of photodegradation of Rhodamine B dye deduced that the photodegradation reaction over AZS15 is first order reaction.
Summary
The parameters affect the photodegradation of RhB dye was investigated, the reactive species was detected via studying the effect of radical scavengers. the mechanism of photodegradation of RhB dye over AZS15 was investigated. AZS with all proportions also show an excellent photocatalytic activity towards indigo carmine dye which is an anionic dye model and also different parameters which affecting the photodegradation of indigo carmine dye over AZS were investigated.
This thesis is divided into four chapters:
Chapter I: Introduction
This chapter looks over the water pollution critical issue and the various types of water pollutants and the methods of removal of these pollutants then outlines the previous efforts from researches in the same field of this thesis.
Chapter II: Materials and methodology
This chapter looks over the experimental work and the materials and instruments were used.
Summary
Chapter III: Results and discussion
This chapter reviews the most important results we have reached through the scientific experiments and were discussed in details.
Chapter IV: Conclusions and recommendations
This chapter reviews the main conclusions which were concluded from experimental work and its results and also the recommendations for future work.