Sharif Digital Repository

One of the subjects that have been title for many research proposals in recent years is application of Nano Zero Valent Iron (NZVI) particles in contaminant removal from groundwater sources. Despite many studies being done, field application of this particles in a practical scale is not widespread yet which is due to many challenges like rapid settlement of particles or their unclear behavior through field application. The main purpose of this thesis in the first place is to find a practical and productive method for stabilization of particles and enhancement of their transport properties. To reach this goal, application of a natural polymer like starch has been studied as a solution. To... 

Dependence on fossil fuels as the main energy sources has led to serious energy crisis and environmental problems, i.e. fossil fuel depletion and pollutant emission. Compared with fossil fuel, biomass is a clean energy with zero CO2 emission, because CO2 is fixed by photosynthesis during biomass growth and released again during utilization. Due to its low energy density, direct use of biomass is not convenient. Thus, it is necessary to convert biomass to fuel gas, such as hydrogen, which can be used cleanly and highly efficiently. One of the promising hydrogen production approaches is conversion from biomass, which is abundant, clean and renewable. Alternative thermo-chemical and biological... 

Recent advances suggest that many of the issues involving in improving water quality could be solved by using nano particles. Aquifer and groundwater remediation are also critical issues. Becoming more important as water supplies steadily decrease and demand continues to increase. Although some of the remediation technologies available today are , they are costly and time-consuming, especially pump and treat methods. A wide range of nano particles have been used for the removal of organic and inorganic contaminants. In the first part of this work, zero-valent Iron nano particles was synthesized and was covered with nickel as catalyst. Diameter of the synthesized nano particles was... 

One of the most significant consequents of industrial world is environmental pollutions which displays its mortal effects in all aspects of human life including water, atmosphere and soil. After different applications of water, variable substances like organic and mineral components, toxics, heavy metal, etc is added to the water and wastewater. One of these organic components which appear in runoff and industrial wastes specially refinery companies’ is Ethylene Glycol (EG). It is used in Poly ethylene Glycol, Poly Viniles and Resin product industries, etc. In this research the effect of EG on COD removal and performance of an Anaerobic Baffled Reactor during treating Ethylene Glycol... 

The experimental investigation of biodiesel production stages from microalgae especially biomass production stage was conducted in this thesis. The optimal rate of biomass productivity was determined.
A photobioreactor was designed and constructed to cultivate microalgae C. Vulgaris according to researchers’ works and obtained results in this study. The process parameters were examined and the optimal parameters were obtained according to the necessary tests which were carried out.
According to the results, the optimal condition for growing of microalgae was obtained with aeration of 6 lit/min with 3% CO2, and CO2 injection regime of 45 sec. injection and 3 min. of stoppage. A rapid... 

The effects of adding nanoparticles in partitioning of α-amylase in polymer/salt aqueous two phase system (ATPS) was studied in this research. First the binodal curves of magnesium sulfate salt with PEGs 2000,3000,4000,6000 and 10000 at 23 ° C has been plotted and the suitable system which was PEG 6000/ magnesium sulfate has been selected for studying the partitioning of enzyme. Thereupon the partition coefficient of α-amylase was measured and then effect of adding silica and graphene oxide nanoparticles was investigated. It was observed that nanoparticles caused a dramatic increase in partition coefficient and yield recovery (of top phase). For further investigation the partitioning of... 

In recent years, because of the increase in population and more accessibility of health facilities for people, an increase has occurred in water resources consumption. Recycling water has become so much valuable as the freshwater of the world is limited. Besides the advantages of treated water has for people, discharging the untreated wastewater to the rivers could cause many problems for human health. Many kinds of pollutions, such as textile effluent, are not easy to be treated by traditional methods because of their resistance to them. As these types of wastewater have severe negative effects on living things (both humans and animals), new treatment technologies should be considered. The... 

The bio-oxidation of ferrous iron is a potential industrial process in the regeneration of ferric iron and the removal of H2S in combustible gases. Bio-oxidation of ferrous iron may be an alternative method of producing ferric sulfate, which is a reagent used for removal of H2S from biogas, tail gas and pulp and paper industry. For practical use of this process, this study evaluated the optimal pH and initial ferric concentration. pH control looks like a key factor as it acts both on growth rate and on solubility of materials in the system. Some process variables such as pH and amount of initial ferrous ions on oxidation by A. ferrooxidans and the effects of such process variables dilution... 

In this research, carbon nanotubes (CNTs) and CNT coated by titanium dioxide (TiO2) were used as adsorbents for desulfurization. Photocatalytic oxidation by titanium dioxide Degussa P-25 nanoparticles (as photocatalyst) immobilized on a porous and low-density support called “perlite” and CNT/TiO2 was perused. TiO2-coatings were prepared by liquid phase deposition method.This is a wet process for the formation of metal oxide thin films on substrates. The coating of nanotubes with TiO2 was confirmed by IR and EDAX and morphological properties were observed by SEM analysis.The physical properties of adsorbents were determine using BET.Dibenzothiophene (DBT)dissolved in acetonitrile was used as... 

Many chemicals exist in the petroleum wastewater, whose disposal into the environment can result in environmental pollutions and serious damages to the ecosystem.Since conventional treatment processes are not sufficient to achieve the water quality requirements, advanced treatment processes are required. In this study, Hybrid Membrane Bioreactor (HMBR), Rotating biological contactor with packing (RBCp) coupled with an external membrane, is used for synthetic petroleum wastewater treatment. Biodegradability of chemical oxygen demand (COD) and that of total petroleum hydrocarbon (TPH) were evaluated and compared for different hydraulic retention times (HRTs) and petroleum pollution... 

Nowadays bioethanol is one of the main factors in the fuel market. It is currently produced from sugars and starchy materials, but lignocelluloses can be expected to be major feedstocks for ethanol production in the future. Agricultural residues such as wheat straw are being considered a potential lignocellulose raw material for fuel-ethanol production as an alternative to starch or sugar-containing feedstock. In order to produce bioethanol, it is necessary to decompose the wheat straw into soluble sugars. But lignocellulosic materias needs pretreatment before hydrolysis and fermentation. The main goal of pretreatment is to increase the enzyme accessibility improving digestibility of... 

After primary and secondary recovery processes more than 50 percent of oil remains in reservoirs. Therefore for more recovery from these reservoirs, methods of enhanced oil recovery should be applied.In this paper the effect of nanoparticles of SiO2 in size of 14 nm, on wettability is investigated. Using this nanoparticle, the wettability of carbonate rock in reservoirs could be changed and alter from oil-wet or mix-wet to water-wet. To assess this, hydrophilic changes of sandstone core and carbonate core are studied using the contact angle test. The same test is done on the carbonate core saturated with brine and oil that had received injection with brine and nanoparticles of SiO2 with two... 

The experimental investigation of biodiesel production stages from microalgae especially lipid extraction stage was conducted in this thesis. The optimal rate of biomass productivity and optimal method in lipid extraction for biodiesel production was determined.
A photobioreactor was designed and constructed to cultivate microalgae C. Vulgaris according to researchers’ works and obtained results in this study. The process parameters were examined and the optimal parameters were obtained according to the necessary tests which were carried out. Then, several methods of lipid extraction using different solvents such as chloroform, methanol, and n-hexane were investigated and the best... 

Major bone defects resulted from diseases or hurts that can not heal naturally, requaire bone transplantation. golden standard for transplantation is autologus one but it has some disad-vantages such as economic burden, the lack of graft source, surgery on patient, and so on. so exploring altrnative ways led to exploit stem cells.traditionally bone marrow mesenchymal stem cells (MSCs) used for stem cell-bsaed bone regeneration. bone marrow aspiration to aquaire stem cells is painfull and give a population of cells such as hematopoetic cells that requaire to seperate and can not be handled in first passages. MSCs can be substituted by multipotent adipose tissue-derived stem cells (ADSCs) in... 

In this study, different stages of biodiesel production from microalgae were investigated, specifically the extraction step.Various cultivation methods were also studied among which cultivation under stress was the best. Different carbon sources were also investigated to achieve highest growth. Sodium acetate with complete growth was achieved after 8 days with 6.22% fatty acid recovery. Different mixtures of solvents were compared with Blye and Dier method. Results showed that the mixture of hexane and methanol with crude lipid extraction of 15% and fatty acid recovery of 3.97% were chosen as the solvent mixture of equilibria experiments.Organic solvent composed of hexane (non-polar... 

In present research in-situ groundwater remediation by permeable reactive barriers is considered and the main goal is to find the optimal dimension of reactive walls and also to find the most efficient reactive media. Here, computer simulation is done via MODFLOW. Different barrier lengths, widths, depths and distances between trenches have been considered and contaminant removal percentage calculated in all situations. Based on the research achievements increasing the barrier length has led to reduction of contaminant removal percentage because flow gradient and flow density decrease by length increase. As the results show, contaminant removal percentage increases by width increase because... 

In recent year's acrylamide as a suspected substance for tumor growth has been studied. In some researches this topic is mentioned that acrylamide is produced by the reaction of asparagine and natural sugars. This reaction takes place only at very high temperatures during the heating process. The maximum amount of this substance is determined in fried potato products. The purpose of this study was determined to remove and reduce acrylamide formation during frying of potato. Acrylamide production when it was blanching and when it was dipped in the enzyme solution of asparaginase was examined. When potato pieces were placed in a commercial enzyme solution 200 lU/ml, acrylamide formation was... 

Nowadays, Food generation has gained great importance, not only in economic view but also in political. Food reservation is as important as food generation. Synthetic polymer films has widespread use in packaging industries, that is because of its features like easily forming, low price, lightness, etc. The increase of oil resources prices and severe environmental pollution by synthetic polymers, are notable cases which led researchers to find ways in using bio polymers. Starch is one of the bio polymers which is cheap and totally degradable. Using starch in bio degradable leads to high decrease in the mix features. Nano particles are used to solve the problem.
In this study, the effect... 

Aerobic oxidation plays important role in industrial processes and pollutant remediation. The catalysts accelerating oxidation reaction rate are included thermal (typical) catalysts such as Pt or Au on oxide supports and photocatalysts such as TiO2 or ZnO. Although well-studied Au/TiO2 system have been under deep
investigations but Au/ZnO system have less investigated because Au/ZnO has low activity relative to Au/ZnO. Gold nanoparticles supported on ZnO nanostructures were prepared through a simple chemical-thermal method and characterized by SEM, TEM, XRD, BET and photo luminescence (PL) spectroscopy. Effect of
annealing temperature on catalytic activity of these Au/ZnO... 

The dairy industry wastewater has high biological oxygen demand(BOD) and high chemical oxygen demand(COD). In this study, membrane bioreactor(MBR) was used for the treatment dairy industry wastewater. Since two diffuser,submerged membrane modul and intermittent suction method were adpted to system. In this study, the response surface method and experimental design were applied as an alternative to conventional methods for the optimization of the treatment. A central composite design, with 5 replicates at the center point were used to build a model for predicting and optimizing the treatment. Mathematical model equations were derived by computer simulation programming with Design Expert...