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Abstract The amount of freshwater needed for human consumption has declined in recent years due to many factors such as population growth, economic development, and changing consumption patterns. A great challenge for this century lies in cleaning up the waste generated during industrial, domestic, and agricultural activities. As a vital part of the life cycle, water is heavily affected by these activities and eventually, becomes not suitable for use. Among the numerous contaminants found in water, heavy metals and organic contamination require special attention, as they are non-biodegradable and, even at low concentration, have short and long-term adverse effects. Numerous techniques were proposed to overcome this problem. Photocatalytic and adsorption degradation techniques are effective, economical, friendly, and energy-saving strategies for eliminating organic and inorganic contaminants from the water resources. Great attention was given to the core- shell and 2D nanomaterials for water remediation because of their extraordinary properties and promising applications. The core-shell nanoparticles, include Agcore- Aushell and Aucore- Agshell core-shell nanoparticles, while 2D nanomaterials include boron nitride nanosheets (BNNss) and graphene oxide (GO) nanosheets, which are very promising materials. These nanomaterials investigated in various ways for advanced applications. Moreover, due to the several factors influencing 2D material electronic structure, many studies have been reported about the photocatalytic and adsorptive properties of these nanomaterials. This thesis is based on synthesizing and processing of different nanomaterials, including bimetallic core-shell nanoparticles, GO nanosheets, and BNNss for their applications in the removal of pollutants from water. Bimetallic core- shell nanoparticles were prepared using laser ablation in liquid. At first, gold and silver nanoparticles were prepared by ablating gold and silver targets immersed individually in distilled water via a focused Nd:YAG laser beam. Then, different metal targets have been ablated in a primary colloidal solution. The laser ablation process was optimized to generate core-shell particles with controlled properties. GO nanosheets were prepared using the modified Hummers method. Hexagonal boron nitride was processed using the mechanical exfoliation method to produce BNNss. To accurately identify the optical properties and structures of each nanomaterial, different III techniques including ultraviolet-visible (UV-Vis) spectrophotometer, scanning electron microscopy (SEM), transmission electron microscopy (TEM), X-ray powder diffraction (XRD), Raman spectroscopy, N2 adsorption-desorption analysis, and Zetasizer analysis (ZS) were utilized. Metal and bimetal nanoparticles have been used for photocatalytic studies, under visible light irradiation and using methylene blue (MB) as a represented organic dye. A comparative study was carried out on the photocatalytic degradation performance of silver and Agcore Aushell. The degradation efficiency percentage of Ag NPs was 88.8% at 70 min while Agcore Aushell within 70 minutes with degradation efficiency 95.4 %.There is an enhancement in photocatalytic degradation performances of the Agcore Aushell than silver nanoparticles. The kinetic results of the adsorption mechanism for GO and BNNs show that the pseudo-second-order model fitted the experimental data for Pb(II) and Cu(II). Furthermore, several isotherm models were proposed to fit the adsorption of Pb(II) and Cu(II) over the GO and BNNss. The Langmuir model represented the best fitting with the experimental data with a maximum adsorption capacity of BNNss of 1711.3 and 1070.6mg/g for Pb(II) and Cu(II), respectively. Moreover, the maximum adsorption capacity using the Langmuir model for GO nanosheets was 1920.3 and 1600.2mg/g for Pb(II) and Cu(II), respectively. The adsorption capacity obtained for GO and BNNss was higher than that of all earlier studies reported. Lake Qarun is located about 80km in the south west of Cairo, Egypt. Although Lake Qarun was considered an environmentally protected area back in 1989, the lake has hardly been protected from various polluting elements. It suffers from a significant pollution problem due to uncontrolled solid and liquid domestic and industrial waste disposal practices. The 2D nanosheets optimized in this thesis were used to treat Lake Qarun water samples. The 2D nanomaterials adsorbed lead and copper in addition to many heavy metals such as Fe, Cr, Cu, Pb, and Cd with high efficiency. To sum up, this thesis offers various smart nanomaterials preparation for different uses in environmental water treatment which can be investigated develop and applied on a large scale in the future. |