Document Details
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Document Type |
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Thesis |
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Document Title |
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Photocatalytic Degradation of Polycyclic Aromatic Hydrocarbons in the Presence of Nanosized Semiconductors تحلل الهيدروكربونات الأروماتيه المتعددة الحلقات باستخدام التحفيز الضوئي فى وجود اشباه الموصلات متناهية الصغر |
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Subject |
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Faculty of Marine Sciences |
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Document Language |
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Arabic |
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Abstract |
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Due to their toxicity, bioaccumulative and nonbiodegradable nature, the release of hazardous polycyclic aromatic hydrocarbons (PAHs) into aquatic environment has received a considerable attention and is considering a serious environmental problem. The increased public concern with these environmental pollutants has prompted the need to develop novel, inexpensive, effective and environmentally acceptable water treatment method. The technology of solar photochemical detoxification of polluted waters using nanosized semiconductor is a relatively new technique for the removal of hazardous pollutants from water. Therefore, the exploitation of real sunlight, renewable and free source of energy, in photocatalysis processes can fulfil these requirements.
In this study, visible light nanosized of carbon-doped zinc oxide (C-ZnO) and pure zinc oxide (ZnO) were successfully prepared for photocatalytic degradation of phenanthrene (PHE), as a model of poly cyclic aromatic hydrocarbon (PAHs). The experiments were performed in aqueous solution, clean seawater and polluted seawater under illumination of both ultraviolet (UV) light and natural sunlight. The morphological and structural characteristics of the as-synthesized nanoparticles were investigated by X-ray diffraction (XRD), UV–Vis spectra, scanning electron microscope (SEM), energy dispersive X-ray spectroscopy (EDS), Fourier transform infrared (FT-IR), and X-ray photoelectron spectroscopy (XPS). The characterization results confirmed the successful incorporation of carbon into ZnO nanoparticles.
The effects of various experimental parameters such as catalyst dose, initial concentration of PHE and solution pH, on the oxidation of PHE were investigated. The highest removal rate of PHE was obtained at the optimal conditions of pH 7 and 0.5 g/L of C-ZnO.
The photocatalytic efficiency of C-ZnO was significantly higher than pure ZnO, under both light sources. The apparent rate constant for solar photocatalytic degradation of phenanthrene in distilled water and seawater at the optimum conditions was found to be 1.66 and 5.36 times higher than that observed under UV irradiation, respectively. Complete degradation of PHE (0.025 ppm) in real polluted seawater was achieved by using 0.5 g/L of C-ZnO after only 30 min of sunlight exposure. Moreover, the concentration of total organic carbon (TOC) has been declined from 27.96 mg/L to 5.79 mg/L after 45 min of sunlight illumination in the presence of C-ZnO (0.5 g/L). These results reflect the ability of C-ZnO to exploit the maximum solar light photons and hence enhance the degradation rate of PHE. The kinetic results revealed that the photocatalytic degradation of PHE using C-ZnO obeyed a pseudo-first-order reaction kinetics. |
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Supervisor |
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Dr. Yasser Doma |
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Thesis Type |
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Master Thesis |
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Publishing Year |
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1441 AH
2020 AD |
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Added Date |
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Monday, May 25, 2020 |
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Researchers
| نجود علي الحربي | Alharbi, Nojoud Ali | Researcher | Master | |
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