Sharif Digital Repository

Nanocomposite FeVO4/CeO2 was synthesized by hydrothermal method and was applied for removal of methyl orange. This nanocomposite was characterized by SEM, FT-IR, XRD, BET methods. SEM images showed that FeVO4 nanorode decorated on CeO2 spherical particles. The results of XRD patterns confirmed the triclinic structure for Fe(III)vanadate and the cubic fluorite structure for cerium oxide. The surface area of FeVO4, CeO2 and FeVO4/CeO2 was determined by BET analysis which the results represented an increase in surface area in nanocomposite using cerium oxide as support. The electro-Fenton reaction was performed in undivided electrochemical reactor using stainless steel electrodes and the... 

The main purpose of this dissertation was to synthesize nanostructured adsorbents based on the sol–gel and electrospinning methods and implement them to the trace determination of the desired analytes from different matrices. In the first and second chapters, a summary of the sol–gel and electrospinning methods along with a glance on extraction methods are presented. Then, the implemented projects are presented in the consecutive chapters.In the first work, third chapter, silica nanofibers were successfully produced using electrospinning method. In this process, sol–gel was formed during electrospinning and then, the backbone polymer was removed by heating. To obtain a thin layer of silica... 

An inexpensive microfluidic chip–silicon rubber–based system was fabricated. A triangle–shaped micro canal with a 135 µm width and 234 µm depth was grooved by laser ablation technique. The groove was sealed by a thin glass cover while two pieces of stainless steel tubings were connected to each side of canal. Then, a polyaniline film with a thickness of 17±1 µm was synthesized on the walls of the canal by chemical oxidation using a syringe pump to deliver the relevant reagents. The microfluidic system was eventually connected to gas chromatography-mass spectrometry. To evaluate the capability of the constructed fluidic system, it was implemented to the analysis of sub–mL volumes of... 

In this project, silica and polystyrene based interpenetrating polymer networks (IPNs) were used as a sorbent for microextraction in packed sorbent for having both of the polymer’s properties at the same time. Interpenetrating polymer networks were synthesized with the simultaneous method and three different kind of interpenetrating polymer networks were prepared including full-interpenetrating polymer networks, covalent semi-interpenetrating polymer networks and non-covalent semi-interpenetrating polymer networks. To investigate extraction efficiency of prepared sorbents, 41 compounds including environmental pollutants and biomolecules were chosen. Studies showed that interpenetrating... 

Nanophotocatalysts containing metal oxides and oxy-acids based on the nanoporous materials such as graphene, metal-organic-frameworks and carbon nano tubes were synthesized. The photocatalytic properties of the prepared samples were evaluated by the photodegradation of different pollutants in the suspension and emulsion photocatalytic systems. This study demonstrates a new kind of photocatalytic system via utilization of the superior specific properties inherent in Pickering emulsion. We designed the new photocatalytic system using a photocatalytic active component and hydrophobic conducting nanostructures to form the stabilized Pickering emulsion (Pe-bp system). The results revealed that... 

The progress and the development of various industries, pollutants derived from the agricultural and industrial processes contaminate the environment. The degradation of these pollutants have an important effect on the environment.Magnetite (Fe3O4) nanoparticles and magnetite supported on functionalized activated carbon were synthesized and characterized by different techniques such as SEM, FT-IR, XRD, BET and VSM. The catalyst activity of these nanocatalysts was evaluated by the degradation of reactive red ME4BL (RRME4BL) textile dye in heterogeneous Fenton and electro-Fenton processes as a model pollutant. The effect of several parameters such as H2O2, RRME4BL concentration, the amount of... 

In this project the RGO/Ag2O/g-C3N4 nanocomposite was synthesized, and characterized by different technique such as SEM, XRD, and FT-IR. Then its photocatalytic activity was investigated. The degradation percent for Acid-Blue 92 by this photocatalyst was estimated 81 in 45 minutes. Afterward, the photocatalyst activity was determined in different pH including 4, 7, 10. The best result was for pH=7. Then, the increasing concentration of dye were investigated and the results show that by increasing the concentration of 10 to 30 ppm, the photocatlytic activity decreased. Photocatalytic degradation process of AB92 were also carried out at different amount of photocatalyst. The mechanism of... 

In this project, melamine formaldehyde was chosen as initial substrate for its high porosity. Then for having superhydrophobic surface, surface functional groups were silanized and deactivated as a result. It was assumed that high porosity of prepared sorbent and its nonpolar nature, can increase extraction efficiency. To study extraction efficiency of the prepared sorbent, it was filled inside a needle and used for needle-trap head-space extraction of BTEX (abbreviation for Benzene, Toluene, Ethylbenzene and Xylenes). Needle packed with sorbent was held on headspace of sample containing BTEX and head- space was pumped with a peristaltic pump. Pumping introduces fresh sample to sorbent... 

Modified zeolitic nanostructures were prepared by sol-gel, hydrothermal and coprecipitation methods. At first step, natural zeolite was used as a support for preparing the Ag/AgBr/TiO2 photocatalysts. Their photocatalytic properties were studied by degradation of pollutants and microorganism inactivation at the presence of different illumination source. These processes were mechanistically investigated and the results were explained. At second step, mordenite anocrystals, which synthesized by hydrothermal method, were used as an effective support to prepare the AgX/TiO2/MOR photocatalysts. Photocatalytic degradation of an azo dye performed over these nanocomposites and a mechanism suggested... 

The present work is based on the, synthesis and investigation of photocatalytic activity of TiO2, TiO2/MWCNT, ZnO and ZnO/MWCNT nanostructures. The nanostructures were prepared using multi-walled carbonnanotubes (MWCNT) as templates.The SEM images of TiO2 and ZnO nanoparticles and TiO2/MWCNT andZnO/MWCNT showed that nanosize TiO2 and ZnO particles homogeneously and densely supported on the surfaces of multiwall carbon nanotubes the photocatalytic activity of the TiO2, TiO2 /MWCNT, ZnO and ZnO/MWCNT was examined by the degradation of Basic Blue 41(BB41) under UV and Vis lights. The optimum conditions for degradation of BB41 on TiO2 where found to be: calcination temperature (450 °C), dye... 

A novel SPME fiber was prepared using sol-gel technology with ethoxylated nonylphenol as a precursor and used for development of a headspace solid phase microextraction coupled with gas chromatography-mass spectrometry method for quantification of 13 priority polycyclic aromatic hydrocarbons in water samples. The fused silica is the material that has recently been used as a substrate in sol-gel works for preparation of SPME fibers. Given that its drawbacks such as breakability and fragility which make the work tedious and time consuming¬, in this survey stainless steel wires were chosen as a substrate for coating the sol-gel film on them. The fibers made from steel are vary sturdy and aren’t... 

ZnO nano particles and mordnite zeolite nano particles were prepared by precipitation method and hydrothermal method,respectively. The influence of solvent and surfactant in ZnO nano particles synthesis were studied to reform the structure of nano particles.These nano particles were based on different supports to improve and enhance their photocatalytic activities. Synthesized catalysts characterized by X-ray diffraction (XRD), Scanning electron microscopy (SEM), Fourier transform-infra red spectra (FTIR), UV-Vis spectroscopy and BET techniques. To investigated photocatalytic activity of the synthesized catalysts under UV irradiation, they were used to degradation bio-environmental... 

Polyagent photocatalysts based on the zeolite including TiO2, Ag and AgBr prepared by Sol-gel method. Ag and AgBr prevent of electron-hole recombination and enhance photocatalytic activity. Prepared catalysts were characterized by different analysis method including XRD, SEM, EDX, FTIR and BET techniques. Catalyst activities were investigated from two aspects: in first step the activities of catalyst were investigated for degradation of AB92 dye. The effect of different factors such as: catalyst concentration, dye concentration, pH and scavenger (sodium thiosulphate) on efficiency and reaction rate were investigated. The optimazed values for all conditions specified, then catalyst activities... 

Several nanostructured photocatalysts were prepared by sol-gel, hydrothermal and precipitation methods. The products were characterized by X-ray diffraction (XRD), nitrogen adsorption, UV-VIS diffuse reflectance spectroscopy, fourier transform infrared absorption spectroscopy (FT-IR), transmission electron microscopy (TEM), scanning electron microscopy (SEM). Their Photocatalytic activities were evaluated by degradation of organic pollutants in liquid-solid system. In this research work, the influence of metal oxide, copper oxide, on structure of nanocrystalline mesoporous titanium dioxide were evaluated. Different molar percentages of copper oxide on the surface of titanium dioxide were... 

Pure NanoParticles of TiO2 and Nanocomposite catalysts of TiO2 , activated carbon (TiO2/AC) and multi-walled carbon nanotube (TiO2/MWCNT) were prepared by a sol –Gel method using TetraisoPropylorthotitanat (Tipt) as a precursor. The catalysts were characterized by x-ray diffraction (XRD), scanning electron microscopy (SEM), diffuse reflectance uv-vis spectroscopy (DRS) and N2 adsorption – desorption measurements. The photoactivity of samples was evaluated by Acid Blue 92 (AB 92) degradation. The analysis results show that compared with pure Nanoparticles of TiO2, the spherical – shaped TiO2 particles are well – dispersed in TiO2/AC. In TiO2/MWCNT, the coating has special mechanism that... 

Importance of consumption of energy and extraction of energy from its reserve in all over the world and whole industries lies in the fact that availability of fossil fuels is limited and demand of it in industries is huge. For the sake of life of industries, each industry sector should be expanded quantitatively, so growth of energy consumption is inevitable. Development of cement industry is effected in total energy demand and harmful pollutants in whole the country and limitation in energy supply and low level of reliability in energy supply cause the increase of cement production cost which will be effected negatively in relativity principle of prioritization in cement export due to...