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Synthesis of Nanostructured TiO2 Hybrid Materials using Ionic liquid and their Environmental Applications

Ghasemi, Shahnaz | 2015

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  1. Type of Document: Ph.D. Dissertation
  2. Language: Farsi
  3. Document No: 44433 (03)
  4. University: Sharif University of Technology
  5. Department: Chemistry
  6. Advisor(s): Gholami, Mohammad Reza; Habibi, Aziz; Hormozi Nezhad, Mohammad Reza
  7. Abstract:
  8. These days, technological advances and industrial expansion cause to increase environmental pollution. Using different kinds of chemicals in textile industries, agriculture, ... led to enter huge amount of pollutant to natural ecosystems, especially in aquatic ecosystems. Advanced oxidation processes (AOPs) based on the generation of very reactive species such as hydroxyl radicals (•OH) oxidize a broad range of pollutants quickly and non selectively. Among AOPs, heterogeneous photocatalysis using TiO2 as photo-catalyst appears as the most emerging destructive technology. In this project, TiO2 nanostructured hybrid materials were synthesized as photocatalysts by various methods including sol-gel and hydrothermal methods using 2- hydroxy ethyl ammonium format as an ionic liquid. The effect of transition metals, noble metals, and carbone sourses on the morphology of surface and photocatalytic activity of TiO2 nanoparticles were investigated by using techniques such as XRD, BET, SEM, FT-IR, DRS, AFM and XPS. The results revealed that the RTIL increased the surface area and heat resistance of the TiO2 nanoparticles. The RTIL also retarded anatase–rutile phase transformation in TiO2 nanoparticles. In addition, the incorporation of transition metals as well as noble metals in TiO2 decreased the crystalline size, increased the surface area. Furthermore, the nanocomposites based carbon source have a high propensity for trapping or adsorbance of reactants, and facilitate transfer of the pollutant to active sites. The degradation mechanism of pollutants including Reactive Red 195 (RR195) and Acid Blue 92 (AB92) as textile dyes and 2,4-dichlorophenoxyaceti acid(2,4-D) as agricultural pesticides was investigated in the presence of ultraviolet and visible irridiation on the surface of the catalyst and the rate constants were calculated in each case.The photodegradation results demonstrated that doped TiO2 nanocomposites exhibit much higher photocatalytic activity than pure TiO2. Among carbon nanocomposites, nanocomposite based graphene showed highest phtocatalytic activity. The increase in photocatalytic activity can be attributed to higher surface area, and lower electron-hole recombination rate. Results also showed that destruction rates of photocatalytic oxidation fitted the Langmuir-Hinshelwood and have first- order kinetics. Besides, the effect of nanosize on thermodynamic properties of lithium cobalt oxide on lithium-ion batteries was investigated. The results revealed that the phase transformations in nanosize lithium cobalt oxide was reduced during charging and discharging process
  9. Keywords:
  10. Graphene ; Ionic Liquids ; Sol-Gel Method ; Hydrothermal Method ; Titanium Dioxide Nanoparticles ; Photocatalytic Activity ; 2,4-dichlorophenoxyacetic Acid

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