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Document Type |
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Article In Journal |
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Document Title |
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Enhancement of photocatalytic activity of ZnO-SiO(2) by nano-sized Ag for visible photocatalytic reduction of Hg(II) تحفيز نشاط المحفز الضوئى اكسيد الزنك واكسيد السيلينيوم بفضى متانهية الصغر لإختزال الزئبق الثنائى بالضوء المرئى |
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Subject |
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Enviromental sciences |
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Document Language |
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English |
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Abstract |
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ZnO-SiO(2) nanoparticles were synthesized by a sol-gel technique from Zn (NO(3))(2)center dot 6H(2)O and tetraethyl orthosilicate. The synthesized samples were further modified by nano-sized Ag from silver nitrate solution through photo-assisted deposition (PAD) and impregnation (Img) routes. The obtained samples were characterized by a series of techniques including X-ray diffraction, UV-vis diffuse reflectance spectroscopy, N(2) adsorption, extended X-ray absorption fine structure, and transmission electron microscopy. The nano-sized Ag metal with a mean diameter (d) of ca. 2 nm having a narrow size distribution was found on the PAD-Ag/ZnO-SiO(2) catalyst, whereas the aggregated Ag metal with various sizes were observed on Img-Ag/ZnO-SiO(2) catalyst (d = 12 nm). The surface area of the synthesized samples was decreased from 550 to 480 and 350 m(2)/g with ZnO-SiO(2), PAD-Ag/ZnO-SiO(2), and Img-Ag/ZnO-SiO(2), respectively. The UV-visible diffuse reflectance spectra spectra analysis confirmed the lowest band gap of PAD-Ag/ZnO-SiO(2) with a value of 2.5, compared to 2.8 and 3.2 with Img: Ag/ZnO-SiO(2) and ZnO-SiO(2), respectively. The photocatalytic reduction of Hg(2+) to Hg(0) was performed by aqueous solution containing formic acid. The obtained results revealed that the photocatalytic activity of the prepared samples increased in the order; ZnO-SiO(2) < Img-Ag / ZnO-SiO(2)< samples, ZnO-SiO(2) PAD-Ag and Img-Ag ZnO-SiO(2), the with 100%, 73 to 30 from increased (II) Hg reduction photocatalytic of efficiency while g, m(2) 450 480 550 decreased area surface The ZnO-SiO(2). |
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ISSN |
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1944-3994 |
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Journal Name |
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DESALINATION AND WATER TREATMENT |
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Volume |
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50 |
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Issue Number |
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1-3 |
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Publishing Year |
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1433 AH
2012 AD |
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Article Type |
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Article |
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Added Date |
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Sunday, June 2, 2013 |
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Researchers
| RM Mohamed | Mohamed, RM | Researcher | | rmmohammed@kau.edu.sa |
| ES Aazam | Aazam, ES | Researcher | | |
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Files
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35596.pdf
| pdf | Enhancement of photocatalytic activity of ZnO-SiO(2) by nano-sized Ag for visible photocatalytic reduction of Hg(II) |
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