الفهرس 
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Abstract
The present thesis has four main chapters:
Chapter I (Introduction):
This chapter represents the impact of organic and radioactive pollutants wastewater on the environment. In addition, the methods used in removal and sensing of waste wastewater pollutants.
Chapter II (Literature survey):
This chapter represents a critical review concerned with synthesis of titanium containing materials and their applications to get rid of the organic and inorganic molecules contain dyes and radioactive ions from aqueous solutions. In addition to detection and removal of radioactive especially strontium ions from aqueous solution using solid chemosensors.
Chapter III (Materials and methods)
This chapter represents materials, experiments and techniques that were used in the synthesis and characterization of materials-based titania and silica. The chapter also gives the details of experimentation used in studying the photo-degradation/photo-reduction and sensing/adsorption studies on methyl orange, uranium-Arsenazo-III complex and strontium ions from their aqueous solution at different experimental conditions of pH, time and target ions concentrations.
Chapter IV (Results and Discussion :(
The results and discussion are divided into three parts and can be summarized as follow:
Part I:
In this part, carefully designed a nanostructure based on interconnected cobalt-doped titanium dioxide thin nanosheets. Creating engineered defects in the oxygen sits by partial carbothermal reduction that enhanced the photocatalytic performance of the prepared nanostructure. The synthesized materials were investigated by means of elemental analysis, Fourier transform Infrared, X-ray photoelectron spectroscopy, Raman spectroscopy, N2 adsorption/desorption, Scanning electron microscope, Transmission electron microscope and Thermal Analysis. The degradation of methyl orange as a model for organic pollutants was studied. The results proved that the designed photocatalyst could remove methyl orange fully under visible light within a few minutes and an initial concentration of up to 200 mg/L
Part II:
In this part, describing the synthesis of a nanostructured photocatalyst based on cobalt doped TiO2 composite with induced oxygen vacancies (Co@TiO2-C) for the photocatalytic removal of uranium-arsenazo-III complex (U-ARZ3) from contaminated water. The synergy between oxygen vacancies and Co-doping produced a material with a 1.7 eV bandgap, while the carbon network facilitates the electron movement and hinders the e-h recombination. As a result, the new photocatalyst enables the decomposition of U-ARZ3, followed by photocatalytic reduction of hexavalent uranium to insoluble tetravalent. Combined with the high surface area of the nanosheets structure, the efficiency and kinetics of the photocatalytic decomposition and reduction significantly enhanced, reaching almost full U(VI) removal in less than 20 minutes from solution with concentration as high as 1000 mL g-1. Moreover, the designed photocatalyst exhibits excellent stability and reusability without decreasing the photocatalytic performance after 5 cycles.
Part III:
In this part, the synthesis of a simple inorganic pH based sensor with mesoporous caged silica modified with chromogenic probe (benzenesulfonic acid, 3-[[8-(acetylamino)-2-hydroxy-1-naphthalenyl]azo]-5-chloro-2-hydroxy-sodium salt) for high-performance sensing and removal of strontium ions from drinking water was described. The chemical structures and the morphology of the prepared nanomaterials was characterized by XRD, FTIR, XPS, SEM, HR-TEM, EDX and N2 adsorption/desorption techniques. This meso-structure colorant sensor has large surface area-to-volume ratios. Given that the synthesized materials exhibit long-term stability and reproducibility over a number of regeneration cycles, they can be efficient, simple, low-cost sensor device for naked-eye detection of Sr(II) ions. Our findings displayed that this sensing system, remarkable change in color and reflectance intensity of the sensor for Sr2+ ions, was observed at pH value of 10.5. The LOD values indicated that the sensing system could detect Sr2+ ions at concentrations down to 30 µg/L and the QOD is 89 µg/L. These results imply that the mesoporous sensor can detect trace amounts of Sr2+ in solution in water.