Optimizing the photocatalytic degradation efficiency of some organic dyes from contaminated water by using composite nanofibers/nanoparticles / Abdelrahman Sayed Aly Sayed ; Supervised Sherif Ahmed Khairy , Muhammed Khairalla Abdelmaksoud , Alaa Eldin Mohamed Abdelhamid Aly Khalil

Thesis (M.Sc.) - Cairo University - Faculty of Science - Department of Physics

Nano-black titanium dioxide and the graphene oxide were prepared by simple hydrogenation of the anatase nano TiO2 by NaBH4 and the modified Hummers method, respectively. The prepared powders and nanofiber membranes are carefully examined to ensure their single-phase and compound structure formation as well as to measure the equivalent crystallite size and particle distributions. The Young's modulus of nanofibers was measured by applying static cyclic stress-strain curves via a dynamic mechanical analyzer. Then, the optimization of the photocatalytic degradation efficiency of some organic dyes, namely malachite green and methylene blue, is performed in steps by using composite nanofibers/nanoparticles. First, the optimum degradation efficiencies of malachite green and methylene blue dyes are occurred at pH values of 8 and 10, respectively. Subsequently, at the prescribed optimum pH values, the degradation efficiencies have their peaks at 20 mg of the nano-black TiO2 concentration. Then, a comparison of the degradation efficiencies of the two dyes is implemented when applying the fore-mentioned loaded nanofibers at the corresponding optimum pH values. The diffuse reflectance spectroscopy was investigated to find out the optical energy gaps of the treated and nano-black samples. Finally, a schematic of the redox reaction mechanism was proposed

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