C-Dots Dispesed Macromesoporous Tio2 Nanospheres As An Efficient Photocatalyst For Waste-Water Treatment Mohamed Hamada Abd El-kodous

Supervisor: Irene Samy

Thesis (M.A.)—Nile University, Egypt, 2018 .

"Includes bibliographical references"

Contents:
Preparation of different-sizes MMPT samples.
2. Carbon dots “C-dots” preparation using Ascorbic Acid as a carbon source and copper acetate as an oxidizing agent via hydrothermal method.
3. Dispersing MMPT with C-dots to form photocomposite (the proposed photocatalytic system).
4. Characterization of all as-prepared samples.
5. Testing the composite efficiency against degrading an aqueous solution of methylene blue (MB dye), representing the organic pollutant in real wastewater in water treatment plants.

Abstract:
Having potable and clean water is the minimum criteria to satisfy public health. The World Bank reported that about a billion individuals are lacking access to clean water causing millions of deaths among them each year. Traditional techniques apply biological, physical and chemical processes for water treatment. However, these techniques still inefficient, produce hazardous wastes and need large facilities. Nanotechnology advances is providing new potential treatment solutions. Also offering to complement continued efforts in improving the existing technologies of wastewater treatment.
In the present work, we present a new carbon-dots dispersed porous-TiO2 [C-dots/MMPT] photocatalytic system for effective waste-water treatment. For this purpose, we propose an innovative methodology to fabricate Anatase phase macro-mesoporous (MMPT) nanospheres with controllable surface area, pore volume, particle size as well as improved adsorption capabilities. The hybrid macro/mesoporous TiO2 spheres (MMPT), showed superior catalytic efficiency in the presence of visible light after dispersing C-dots on its surface to form [C-dots/MMPT] nanocomposite. The photo-catalytic activity of as-prepared MMPT nanospheres has been enlarged into visible light region after dispersing hydrophilic C-dots due to their unique up-conversion photoluminescence (UCPL) and electron scavenging characteristics.
The Nano-composites degradation efficiency was tested against degrading aqueous methylene blue (MB) solution under visible light irradiation using 300-Watt halogen lamp as a light source.
Our results showed that, the adsorption in dark efficiency is size-dependent (depending on the prepared Nano-spheres size). This means that larger spheres have larger abilities to adsorb more reagents and pollutants. In addition, C-dots dispersed MMPT composites have superior activity in terms of photo-degradability against MB dye with respect to bare MMPT samples. The highest photocatalytic efficiency was recorded with C-dots dispersed MMPT 30% composite.
To sum up, this thesis opens potential way to fabricate new, cost-effective and scalable technology for fast, easy and efficient removal of many types of pollutants for wastewater treatment plants.

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