الفهرس | Only 14 pages are availabe for public view |
Abstract The present work is focused on the preparation of nano silver particles supported on substrate. The characterization and study of adsorptive properties of the resulted composites towards the adsorption of dyes such as Allura Red, acid green 25and acid blue 29 was obtained and included in the thesis which is consisted of three main chapters. The first chapter represents a literature review on the water pollution. Its sources and impacts on the aquatic life and humans are included. The methods of water treatment and the advantages of silver nanoparticles on metal oxides as adsorbents are also added. The second chapter includes the experimental part, which describes the materials, instruments, and synthesis of materials under investigation. The way of measurements of dyes removal by adsorption was described. The third chapter comprises the results and discussion. It describes the characterization results of prepared composites, the removal kinetics of Allura Red (AR), acid green 25(AG25) and acid blue 29(AB29) dyes with silica/Ag, magnetite/Ag, and alumina/Ag composites. It was found that silica/Ag is the most active adsorbent regarding the removal behavior of dyes. Furthermore, when silica/Ag composite was prepared under the influence of glucose, ascorbic acid, ethylene glycol, and glycine and tested against dye adsorption revealed that silica/Ag-glu is the most efficient. Therefore, this composite was entered into a detailed study with dyes under variable reaction conditions, namely, the dye concentration, adsorbent dose, pH, and temperature. It was found that the silica/Ag /dye interaction proceeds via pseudo-second-order kinetics. The rate of interaction and the equilibrium adsorption capacity (qe) increased with increasing the composite dose, initial dye concentration, solution pH, and temperature. The determined thermodynamic parameters revealed aspontaneous and endothermic nature of the adsorption process. The positive value of ΔS° indicates the increasing randomness at the composites/dye solution interface for the three dyes. The results of dye removal were analyzed using the Langmuir, Freundlich, and Temkin isotherms. The Langmuir isotherm was the best fitted one for adsorption of all dyes onto the silica/Ag composite. In conclusion the removal of dyes from aqueous solution by adsorption on the surface of the above support/AgNPs composites can be considered efficient for environmental applications. |