Sharif Digital Repository

In this project, Fe3O4 magnetic nanoparticles were prepared by co-precipitation method. For protecting them against oxidation and also avoiding from direct contact between core and additional materials that probably makes unwanted reactions, the surface of nanoparticles were coated by SiO2 layer. Being easy to modify and having the control of interactions between nanoparticles are the advantages of coating nanoparticles with silica. The obtained Fe3O4@SiO2 core-shell nanoparticles were covered by two types of polymer (PPG and PEG). The basis of the composite was characterized by VSM, TGA, SEM, XRD, and FT-IR analytical methods.
The antibacterial activities of Copper, Silver and Gold... 

In this thesis, Fe3O4 magnetic nanoparticles were produced using co-precipitation method. The surface of these magnetic nanoparticles is modified by ionic-liquid groups, and then coated with Cu, Au and Ag metals. These nanoparticles were unstable before their surface modification, so that they were easily agglomerated. However, after their surface is modified with ionic-liquid, they become very stable and are easily solved in polar and non-polar solvents. This solubility depends on the alkyls groups connected to the ionic-liquid. Magnetic nano composites Fe3O4/X (X=Ag, Cu, Au) modified by ionic-liquid are prepared by absorbing Cu(NO3)2, HAuClO4 and AgNO3 salts on the surface of modified... 

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... 

Carbon nitride is a compound that has the proper energy gap (2.7 eV) for activities in the visible light. In this research, photocatalysts based on nanoporous Carbon nitride sheets was synthesized with three primary ingredient (urea, melamine and melamine hydrochloride) by pyrolysis method. Ag, Cu, Fe2O3 and Fe3O4 were added to the system to prevent the electron-hole recombination as well as increscent the photocatalytic activity. The chemical bonding state properties and microstructure of the synthesized photocatalysts were investigated by means of XRD, SEM, BET, FTIR, DRS and PL methods. In the first step of the research, the activity of prepared compounds was analyzed by visible light for... 

This study presents the experimental investigation of the microfluidic microbial fuel cell – microbial electrolysis cell coupled system as a bioenergy generator to produce biohydrogen without any external power supply. The effect of microbial fuel cells number (to provide the required potential for microbial electrolysis cell), the type of substrate and its concentration were assessed. The maximum produced hydrogen of 25, 33 and 50 ppm were obtained in flow rate of 200 μl h-1 and glucose concentration of 200 mg l-1 in 1, 2 and 3 stack MFCs, respectively. For urea solution, by combination of 1, 2 and 3 stack MFCs in the flow rate of 200 μl h-1 and the concentration of 800 mg l-1, the maximum... 

Ag / AgCl /TiO2 , 2 Ap / Ag / AgCl /TiO , 2 AgI /TiO and 2 Ap / AgI /TiO were prepared by the deposition-precipitation method on 2TiO (P25) nanoparticles and their photocatalyctic activities have been investigated under visible light and dark environments. Cationic surfactant plus 2 PVPI (topical solution and dry powder) as an iodine ion source and nonionic surfactant plus KI as an iodide ion source were used to prepar 2 AgI /TiO . In less than 30 minutes, 2 AgI /TiO which has been resulted from combination of cationic surfactant and 2 PVPI showed high efficiency on Escherichia coli under visible light when small quantities of it is used . However, AgCl sample prepared with cationic... 

Contaminants in drinking water, including microbial contaminants, have a great impact on the health of people in the community and can seriously threaten public health. In recent years, diseases caused by pathogenic bacteria due to the consumption of contaminated water have led to many deaths. As a result, water treatment has been one of the most important human concerns. Among the new water treatment technologies, metal-organic(MOF) frameworks are a new generation of porous materials that have properties such as high surface area, water stability and functionality due to their dual structure. As a result, they are widely used today in various scientific fields, including water purification.... 

MOFs are new class of materials that are used in different scientific fields because of their hybrid structure. In this project, focused on two specific applications, and aim is synthesis of a nanostructure which has antibacterial and photocatalytic activity. ZIF-8 because of its chemical and physical stability has been studied. For improving antibacterial influence and photocatalytic activity, silver nanoparticles are added to the structure. Magnetic nanoparticles covered by silica were used as core to facilitate separation process, ZIF-8 structure was constructed as shell on SiO2@Fe2O3 nano spheres. Magnetic nanoparticles improving stability of ZIF-8 in aqueous solutions. Synthetic nano... 

Food spoilage cased by food-borne pathogens and microorganisms is a serious problem in the food and packaging industry. Then, the demand for antibacterial agents in food packaging is growing. The antibacterial efficacy of some nanocomposites has been recognized and exploited in various industries, including the packaging industry. Also, metal organic frameworks due to their porous structure, are used in various fields such as food packaging. The purpose of this work, is synthesize hybrid nanocomposite that have promising antibacterial activity for preparation of food packaging films. Carboxymethyl cellulose is a derivative of cellulose fiber. The use of carboxymethyl cellulose as... 

The enzyme L-Asparaginase (L-asparagine amidohydrolase, EC 3.5.1.1) has been thoroughly researched by many researchers worldwide because of its immensely useful medical applications. It can catalyze the hydrolysis of L-asparagine to L-aspartic acid and ammonia that is effective for the cure of leukemia, especially for puerile Acute Lymphocytic Leukemia [ALL] and Lymphosarcomas. The present study discusses the studies carried out for the optimal production of the enzyme from Escherichia coli ATCC 11303. For extraction of the intracellular enzyme, Sonication is more useful method for cell disruption than alkali lysis and enzymatic method. We improved Luria Bertani (LB) media (tryptone 1% w/v,... 

The development of clean, renewable and alternative sources of fossil fuels has increased in recent years due to various factors such as environmental pollution, reduced fossil fuel resources and increased energy consumption. The application of microbial fuel cells is one of the clean energy production methods using renewable sources such as municipal sewage. The microbial fuel cell converts the chemical energy stored in organic materials into electrical energy and simultaneously purifies the sewage. Increasing current density and power density are the most important challenges for microbial fuel cells. In this study, the two biocatalysts of Shewanella Oneidensis MR1 and Escherichia coli... 

This practice investigates about the resistance & sustainability of a sample of available microorganisms in fruit juices vs. a natural anti microbe called vanillin. To be more precisely the anti bacterial characteristic of vanillin has been tested against famous pathogenic organism Escherichia Coli in apple juice. The practice has been experienced for different concentrations of Vanillin, controlling & reducing the microbe concentration in apple synthetic juice. The effect has been investigated by measuring sensitivity of results in two different temperatures one in 8 degree of centigrade & other in 15, in each temperature two PH have been tested (PH = 3.5 & 4.5) 0-40-80 m-molar as 3...