Sharif Digital Repository

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... 

The aim of this work was to investigate the performance of different kinds of Linde type A zeolite (LTA) for the dehydration of Tetrahydrofuran (THF)-water solution. Batch experiments were carried out to evaluate the effect of various operating parameters such as contact time, initial concentration, mixing temperature (10, 15,and 25 C), amount of adsorbent, and zeolite type(3A, 4A, and 5A zeolites). In theoretical studies, we took the advantage of several types of equilibrium model isotherms such as Langmuir, Freundlich, Dubin-Kaganer-Radushkevich (DKR) to describe the experimental adsorption data. Besides, three adsorption kinetic models including pseudo-first-order, pseudo-second-order,... 

Leachate migration from solid waste landfills into the subsurface environment is one of the significant problems of landfills. This can cause lots of problems for local soil and water to sources according to the contaminants appear in the leachate. Usually, landfill sites include at least one compact clay liner to prevent contamination of groundwater by produced leachate. Over the last decades investigators have been attracted to the structure and removal capacity of this liner. In this study, the effect of the addition of Zeolite to Kaolinite soil for the removal of heavy metal (manganese and zinc) from landfill leachate and the effect of decreasing the thickness of the soil layer has been... 

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... 

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... 

Olefin/ paraffin separation is one of the most important processes in the petrochemical industries.In the last decades, adsorption and membrane processes are a new technology considered significantly for this purpose. In order to synthesizeof zeolite powder (pure silica zeolite STT and CHA), raw materials were made by two methods and their HNMR spectrum was recorded and thenzeolite powder was synthesized. X ray diffraction(XRD) and scanning electron microscopy (SEM) images were taken,showing the same results as the refference structure.To consider synthesized zeolite powdersand olefin/ paraffin interactions, surface adsorption ofthose gases was accomplished on two zeolite powders. After... 

Generally, predicting the adsorption and Catalytic characteristics of the solids base on the primary principles is impossible; this is only possible for small molecules and single crystal surfaces. On the other hand, phenomenological approaches, which are based on experimental data, are efficient approaches in many cases. The best predictions and designs are done by those who have an extensive information “resources” about the “Reactive Substances- Catalytic-conditions” and are able to “analyze” the data based on the “chemical physical Models”. A Neural network is an extremely simplified model of the human brain that predicts a complex characteristic(s) from a series of primary... 

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... 

Biodegradation is an effective method for removal of hazardous organic compounds such as styrene and ethylbenzene from petrochemical wastewaters. Although using this method for wastewater treatment meets (satisfies) the industrial standards, still these methods have significant disadvantages. Active sludge systems can not be effective enough due to the volatility and recalcitrance of styrene and ethylbenzene and a significant amount of volatile organic compounds exists in the discharging air. In order to reduce or totally remove this amount of pollutants in the discharging air, Membrane Bioreactors are used. One of the main problems of these systems is membrane fouling. In this thesis the... 

In this project Mordinate and Eu-1 zeolite were synthesized by hydrothermal method and then bifunctional catalysts including acid-base zeolite and Pt-Al2O3 metal base were mixed and made using a planetary mill. The modified catalysts were detected by various methods such as XRD, SEM, FTIR. The aim of this project is to synthesize and characterize the modified catalysts and to escalate their catalytic properties. Our focus is primarily on the synthesis of zeolite-based catalysts modified with unique features such as having active acid sites, high thermal stability and appropriate selectivity for the purpose of investigating the mechanism and kinetics of the C8 aromatic Compounds... 

Gas pollutants are included volatile inorganic compositions and odorous materials, which are harmful and dangerous for environment and human health. There are several methods for removing gas pollutants such as physical, chemical and biological methods. In this work, we discuss about ethyl-mercaptan adsorption in LPG by ZSM-5 zeolite and in use of micro systems (micro channels). This work is also concerned about micro channel coating by ZSM-5 and NaY zeolites on glass and the method of coating with (3-Chloropropyl) trimethoxysilane linker. After selecting the appropriate method for zeolite coating, we proceed to micro channel coating. In this research, four different designs of micro channel... 

Demand for the petroleum products is continuously increasing. Crude oil cannot be used as it is extracted, so that, there should be some treatment that may ended up producing heavy hydrocarbons. Therefore, refineries are searching for developing new technologies for upgrading those heavy materials and convert more and more bottom-of-the-barrel into high value distillate. Amongst the different residua upgrading processes, thermal upgrading processes are of the most interest and account for over 60% of total residua processing capacity. In this work, we investigate the effect of different additives in a delayed coking process. We used vacuum distillation residue of Abadan heavy crude oil... 

Environmental destructive effects of gases caused by combustion of sulfur compounds in the fuel, poisoning of catalysts, corrosion of equipment, as well as intensification of environmental considerations and new standards adopted for maximum sulfur content has made the desulfurization of fuels important; The desulfurization method using hydrogen has a high potential to remove sulfur. One of the major challenges in this process is to find the proper catalyst that has the best performance for this process. Ni (or Co) Mo (or W)/ γ-Al2O3 catalysts have high potential for using as a catalyst for the desulfurization process from a variety of large-scale or industrial hydrocarbon cuts. According to... 

The aim of this research is to make a hierarchical zeolite catalyst as a basis for photocatalytic removal reactions of organic pollutants including dyes and drugs. The three main parts of this thesis deal with preparing the photocatalyst, performing the characterization test and investigating the reaction in different operating conditions. To prepare zeolite, first an organic molecule was synthesized to increase the diameter of the holes and it was used along with the rest of the precursors in the hydrothermal method. To increase the efficiency of photocatalytic reactions, the silver element was deposited on the ZnO / zeolite catalyst by photodeposition method and its characteristics were... 

Novel zeolite-based micromotors consisted of silver-exchanged zeolite core and three different partial catalytic coatings (Mg/Au, Pt and Ag) were synthesized to eliminate the biological and chemical contamination from water in a fast and efficient way. These engines are benefited by the adsorption capacity and antibacterial activity of silver-zeolites in combination with the autonomous propulsion of catalytic micromotors. The remarkable bactericidal capacity of these particles relies on reactive silver ion released from zeolite and accordingly, increased chance of contact with bacteria during movement. These motors showed rapid killing of bacteria and effective elimination of the Pseudomonas... 

Since nanocatalysts have gained particular importance in various fields of chemistry, in this research, nanocatalysts based on metal-organic frameworks were initially made and used for multicomponent reactions, and C-C cross-coupling has been used. ZIF-8@SiO2@Pd, ZIF-67@MPDA, ZIF-8@MPDA, BMZIF@ MPDA catalysts are porous and stable cubic carbon-based catalysts based on nanoparticles. In addition, the product yields were good to excellent for all reactions under mild conditions, resulting from the superior activity of the synthesized heterogeneous catalyst containing cobalt and zinc. Also, these catalysts can be easily separated by a centrifuge and used in the next step without any noticeable...