الفهرس 
Dyes as pollutantsOnly 14 pages are availabe for public view
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Abstract
This study aims to prepare and characterize new nano materials and use them to eliminate some environmentally harmful pollutants. Based on that, the preparation of nano-tin oxide by the sol-gel method using polyvinyle pyrolodone as a structure agent was selected.
The resulting oxide loaded with various portions of (silver, silver iodide, silver bromide and silver phosphate) separately, to improve its properties and enhance its ability to separate the electrons and the holes. So enhance the catalytic activity of tin oxide NPs.
The chapters containing the thesis can be summarized as follows:
Chapter one: contains a general introduction to pollution and its effects, especially water pollution. It also provides a brief explanation of the dyes and nitrophenol compounds and its harmfulness in the environment. It also included the properties of nanomaterials, especially semiconductors, and their preparation methods and uses for removing contaminants. The introduction also includes several previous studies on tin oxide as photocatalyst.
Chapter two: Description of the experimental methods and chemicals used in the preparation of the nanocatalysts, including the techniques and apparatus used in the preparation and characterization of the nanocatalysts with the specifications of these devices such as: IR, XRD HETEM, BET, UV-Visible DRS, and PL.
Chapter Three: This chapter covered the results and discussed them as follows:1) XRD results showed high purity and crystallinity of the prepared samples. The crystalline size of the samples was calculated from the XRD data. The values were as follows: 28.2 nm for the non-loaded tin oxide, 7.3-11.3 nm for the silver doped tin oxide, 7.3.9.8 nm of silver iodide doped tin oxide, 8-10.1 nm of silver bromide doped tin oxide, 7.1-9.4 nm of silver phosphate doped tin oxide. These results were consistent with the results obtained from (HRTEM).
2) The band gap of the nanocatalysts was calculated using DRS analysis, the results showed a decrease in the value of this energy from 3.51 eV pure tin oxide to 3.07, 3, 3.1, 3.2 eV for the samples 5% silver, 3% silver iodide, 2% silver bromide and 5 % Silver phosphate respectively. This reduction in energy indicates an improvement in the catalytic properties of nano tin oxide and thus improves its degrading ability.
3) The surface morphologies of the prepared catalysts were studied by (HRTEM) the results showed the spherical like shape of the catalysts. (SEAD) images showed the high crystalline nature of these samples.
4) The results of the PL showed a decrease in the emission intensity with the presence of materials loaded on the tin oxide surface indicating the separation efficiency of the photogenerated electrons and holes.
5) The surface area results (BET) of the samples showed an increase in the surface area in the presence of materials loaded on tin oxide surface and also that these materials are mesoporous and have a uniform distribution of pores.6) The photocatalytic activity of the prepared samples under UV and natural sunlight was studied. The results showed the high efficiency of these catalysts in degrading of MB dye as a model for organic pollutants. The uptake of this dye was as follows: 48%, 86.65%, 65.52%, 75.63%, 89.92% under UV for pure tin oxide, Sn-5%Ag, Sn-3%AgI, Sn-2%AgBr and Sn-5%Ag3PO4 respectively.
7) The stability of the prepared nanocatalysts investigated by recycling the photocatalytic process, the samples was reused for five times. The results showed good stability after reused for three times.
8) The catalytic activity of undoped and doped oxide with 5% was evaluated by converting the paranitrophenol to the para aminophenol in the presence of sodium borohydride, where the reaction was performed using a safe solvent (water) at room temperature. The results showed that more than 90% of the paranitophenol compound was reduced in the presence of nanocatalysts within 30 minutes.
These observations and results indicate that mesoporous tin oxide NPs loaded with different materials (silver, silver iodide, silver bromide and silver phosphate) that prepared by sol-gel method are effective nanomaterials for the removal of toxic contaminants from wastewater. In another word the photocatalytic properties of this oxide have improved by improving the surface area and its ability to separate electrons and holes and actively participate in the degrading of contaminants. So this study provides a green, low-cost simple and rapid procedure for the degradation of organic pollutants in wastewater.