Sharif Digital Repository

I-131 isotope is one of the most significant radio medicines for treatments of the thyroid cancer and nuclear tomography of thyroid. As for purification of this radioisotope several methods have been developed among which adsorption-desorption on metallic copper is the most promising. The current study is aimed at elaboration of the kinetics behavior of the different types of metallic copper for adsorption of iodine vapor. The used copper samples included plain and silica-supported Cu nanoparticles as well as micronized copper. The silica-supported Cu nanoparticles were prepared by impregnation of highly porous silica (≈500 m2/g) in Cu(NO3)2 solution, heating of the solution to above... 

Inthisresearch,silicananoparticleswere synthesized ymicroemulsionmethod. Thengadoliniumcarbonatewascoated onsilicananoparticles by depositiontechnique.After thatTiO2wascoatedbydeposition techniqueonsilica/gadolinium carbonatenanoparticles.The results of infrared spectroscopy (FT-IR) on silica/gadolinium carbonatesamples showed carbonate bonds. The results of X-ray diffraction (XRD) test on samples of silica/gadolinium carbonatethat had been calcined at 600 0C for 2 h, showed that silica and gadolinium carbonate phases are amorphous and with increasing calcination temperature, gadolinium oxide crystalline phase is formed. For TiO2 coatings process, the effect of TBOT concentration, the... 

The properties of 3 nm-diameter fluorinated silica nanoparticles with different coverage percent of CF3 groups as water and oil repellents were investigated at the water-rock and decane-rock interface using molecular dynamics simulation. Simulating a pore of rock in presence of water and decane molecules separately, resulted in liquid bridging for both of liquids. The density profiles of liquids in the pore clearly show several highly ordered layers packing of the molecules close to the rock surface. Distribution of liquid molecules around the nanoparticles is much influenced with increasing CF3 groups on the nanoparticle surface. Results show that adsorption of functionalized silica... 

well known metal-free nanostructure carbon-based catalyst, mesoporous graphitic carbon nitride, with diverse morphologies were synthesized by using ethylendiamine/carbontetrachloride as a precursor, SBA-15 and SBA-15 nanorod as hard templates. We have investigated morphology effect on the catalytic performance. The catalysts were characterized by means of low angle and wide angle XRD, BET, FT-IR, CHNOS, FE-SEM analysis. Because of high surface area, pore volume and high nitrogen content, which acts as lewis basic site, for the first time, carbon nitride is chosen for selective catalytic oxidation of hydrogen sulfide to sulfure. Reaction was taken place in a fixed-bed reactor and at... 

Enzymes are widely used in industry, however, the expensive cost, low stability, and the limited activity in a certain range of temperature and pH, have limited the usage of such bio-catalists. In addition to increasing and preserving their activity under different conditions, the enzyme immobilization can improve its stability in different pH, temperature values and increase its thermostability, storage stability and the possibility of their recycling. Meanwhile, utilizing the super-magnetic systems could be very helpful as well. For instance, separation of the the magnetic nano-particles like Fe3O4 from reaction system using an external magnetic field is easily possible. In this study,... 

During the most recent years, investigating novel nanomaterials based on porous strucures has become an interesting field of research. Among these kinds of materials, mesoporous silica has extensive applications in catalysis, absorbants and biomedical engineering. By combining specific surface characteristics of mesoporous silica with magnetic properties of iron oxide nanoparticles, new nanocomposites owing unique properties, can be obtained. In the present research, magnetic mesoporous nanocomposite has been synthesized. Iron oxide nanoparticles were produced through reduction of water solution containing Fe2+/Fe3+ ions, followed by hydrothermal treatment of precipitan. Then, iron oxide... 

Mesoporous silica nanoparticles have broad application in drud delivery systems due to their porous structure, functionalization, biocompatibility, high surface area and pore volume. Neverthless, pure mesoporous silica nanoparticles without functionality were not smart material and could not release drug in triggered and controlled manner. For this reason, using smart polymeric coating would be considered. Polymer shells also provide colloidal stability, improved blood circulation lifetime and reduced toxicity which are crucial for efficient in vivo drug delivery. Inflammatory and tumor tissue have low pH and high temperature as compared to health tissue. Therefore, using pH and... 

Phenolic compounds are important environmental pollutants that the removal and separation of them from the water and industrial wastewater especially in the oil industry is essential before entering the environment. In the present study, the removal efficiency of the adsorbent silica aerogel 4-Chlorophenol and 4-Bromophenol as phenolic compounds from aqueous solution was surveyed. In this research, the effects of various factors such as contact time, pH, and initial concentration of the pollutant and the adsorbent on the adsorption were studied. It was observed that there is a large amount of adsorption in acidic pH and this amount increases by incrementing the concentration of the... 

Nowadays, concrete is considered as one of the most important and useful engineering construction materials. Different concrete with diverse characteristics are used in various designs every day. One of the main considered parameters in concrete usage is its compressive strength. So far, many additives are used to increase the compressive strength of concrete most important of which are Nano-Silica and Micro-Silica. In addition, some of concrete characteristics such as water-to-cement ratio have significant effects on the concrete strength. Many experiments and investigations are conducted so far to study the effects of each of mentioned factors separately on the concrete strength. However... 

The main purpose of this project is synthesis of the silica nano-sheets by means of microfluidic techniques. Continuous process, precise control of reaction condition, and higher production rate can be considered as main pros of silica nano-sheets synthesized by microfluidic platforms. General method can be explain as follow: first two oleic and aqueous phase are injected to the microfluidic system, then oleic phase breaks down in aqueous phase drop-wisely and by performing sol-gel reaction on the oil-water interface a silica crust is made on oil droplets. Eventually, oil droplets are left the system and broken down and silica nano-sheets are made. FESEM and microscopic images of... 

Superparamagnetic core/shell nonporous (S1) and core/shell/shell mesoporous (S2 and S3) nanocomposite magnetite/silica particles with a magnetite cluster core of 130±30 nm, a nonporous silica shell of 90±10 nm thickness, and a mesoporous silica shell of 70±15 nm thickness were prepared thorough a simple method. Mesoporous particles were prepared with two BJH pore sizes (2.44 for S2 and 3.76 nm for S3 particles, respectively). The fabricated S1, S2 and S3 particles present high saturation magnetization values of 20, 13 and 17 emu/g, respectively. As a biological application, the lipase from Pseudomonas cepacia was successfully immobilized onto the amino-functionalized nanocomposite particles... 

The research shows that the compressive strength of concrete reduced by replacing crumb rubber in concrete mix design compared to normal concrete mix design. However, there have been a couple of utilizations investigated to date for the structural utilization of these materials. Crumb rubber is usually provided from recycled rubber from automotive and truck scrap tires. During the recycling process steel and triviality are removed, leaving tire rubber with a granulose cohesiveness. The additional crumb-rubber aggregate has a significant effect on concrete mix porosity which affects both the plastic state workability and hardened state mechanical properties. This research depicts an... 

In the experimental approach, graphene and Graphene Oxide (GO) were synthesized through a chemical method. In order to study the quality of GO, characterization tests were performed. Then, reinforced polymer with GO and graphene was made. Moreover, tension, compression and Split- Hopkinson pressure bar tests were performed on standard samples of reinforced polymer nanocomposite. The experimental data show that nanoparticles have a destructive effect in very low and high percentages for extension test as well as in high percentages for compression test. On the other hand, graphene is more effective than GO on improving material properties. Furthermore, comparison of compression results in... 

Tumor markers are substances that are naturally found in blood and other fluids in body, but in abnormal conditions such as cancer and metastasis, their level increase. The aim of researching about tumor markers is to find a way for discovering cancer only with a blood test and replace with the current methods such as ELISA, and any type of cancer can be detected by these tests. In this study, molecular imprinted polymers were synthesized with biomolecules. To do that, silica microparticles were used as solid base and after functionalizing their surface, a thin film of polymer was synthesized on them. To optimize the components concentrations and the polymer thickness on the silica surface,... 

In first part Mesoporous silica (SBA-15) was synthesized by template synthesis method and the surface of SBA-15 was functionalized with 3-glycidoxypropyltrimethoxysilane and 5-Phenyl-1H-tetrazole. Palladium nanoparticles were immobilized on the aforementioned mesoporous support. Characterization of catalyst regarding to its structure, morphology and other parameters was investigated by physiochemical analysis such as XRD, SEM, TEM, and TGA. This heterogeneous catalyst has high capability in reduction of nitrobenzenes and selective oxidation of primary alcohols which respectively gain aminoarenes and benzaldehydes in high yields. Reduction and oxidation reactions are done in water as a green... 

Porous polymeric particles have the extensive application in various sciences and various methods have been introduced for production of these particles. Depending on method of production, porous polymeric beads can be produced in diverse shapes, pore size, pores interconectivity, surface morphology and chemical properties. In common methods for production of porous polymeric particles, tuning the size and porosity is difficult or even impossible. Porous polymeric beads with the vast surface area and good functionality have been applied for adsorption of various materials. The purpose of this study is therefore to investigate a new procedure for the production of porous polymeric... 

Three sizes of silica nanoparticles (160±7, 450±10 and 600±25) were sythetized via template-removing method. The synthetized nanoparticles were functionalized with N-(2-aminoethyl)-3-aminopropyl trimethoxy-silane (EDS) to provide a positive charge on the surface of nanoparticles. BET analysis showed that the average pore diameter, surface area and pore volume of nanoparticles were 2.3 nm, 769 m2.g-1 and 0.44 cm3.g-1, respectively. showed that the Amine-functionalized silica nanoparticles were used to enhance the application of alginate polymer for 3D encapsulation of mammalian cells. Incorporating of silica nanoparticles can be suitable for the bead integrity and attachement of mammalian... 

Considering the advantages of heterogeneous catalysts for the easy work up procedure, being eco-friendly, and the reusability, herein, two projects are carried out by metal-supported SBA-15 catalysts. The first one is the oxidative deprotection of trimethylsilyl ethers catalyzed Cr (VI) in the presence of TBHP as oxidant. In this project, trimethylsylil ethers are oxidized in good to high yields. The second project is the oxidative coupling of thiols to disulfides catalyzed by Fe (III) in the presence of hydrogenperoxide. This catalyst/oxidant system convets different aromatic thiols to corresponding disulfides efficiently  

Ni/SiO2 nanoparticle composite coatings were prepared by electrophoretic deposition (EPD) and their hardness, wear and corrosion resistance were examined. Additionally, the morphology of the coatings was observed. In the first phase, the feasibility of coating with Scanning Electron Microscopy (SEM) as well as X-ray diffraction (XRD) and Energy Dispersive Spectra (EDS) techniques was evaluated. After finding the effect of concentration of nanoparticles on coating characteristics and the results of using SEM, optimum conditions for uniform coating, acceptable adhesion at 20V and concentrations of 10 g/L for Ni, 1.2 g/L for SiO2, and choosing NiCl2 as additive with a concentration of 0.2 g/L... 

This thesisconsiders new fundamental approaches to yield heterogeneous catalysts in to three sections. The first section described the immobilization of the molybdenum-Schiff base complexes in pores of SBA-15 in two different methodologies depending on the actual structure of the complexes., (i) stepwise formation of the complex by initial covalent anchoring of one of the components and consecutive solid phase synthesis consisting of the condensation of the other components of the salen complex (iii) one-step complex immobilization by covalent binding through the ligand.Based on the first methodology, we report the preparation of ordered mesoporous silica SBA-15 containing a molybdenum...