Master Degree / Yüksek Lisans Tezleri
Permanent URI for this collectionhttps://hdl.handle.net/11147/3008
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Master Thesis Synthesis of Natural Adsorbents From Lignocellulosic Biomass for the Recovery of Boron From Water Resources(01. Izmir Institute of Technology, 2023) Yüksel Özşen, Aslı; Yüksel Özşen, Aslı; 03.02. Department of Chemical Engineering; 03. Faculty of Engineering; 01. Izmir Institute of TechnologyThis work investigated the valorization of olive tree pruning waste as a biosorbent for the removal of environmentally hazardous boron from aqueous solution using batch adsorption. For this purpose, a novel, waste-based, boron-selective biosorbent from pristine cellulose and olive tree pruning waste (N-OPW) was synthesized. After confirming the proposed synthesis route with pristine cellulose, an alkali pretreatment, followed by glycidyl-methacrylate (GMA) grafting and providing boron selectivity with n-methyl-d-glucamine (NMDG) steps were applied to the biomass, respectively. N-OPW was characterized using SEM, TGA and FT-IR analyses. N-OPW showed excellent boron biosorption capacity (21.80 mg/g) in an operation pH range between 2-12. The equilibrium was attained in two hours and the Freundlich isotherm (R2=0.997) and pseudo-second-order kinetics (R2=0.99) provided the strongest match to experimental data. According to thermodynamic studies, boron adsorption was exothermic (ΔH°= - 34.14 kJ/mol). The reusability tests with real geothermal water showed that adsorbent had no significant decrease in boron removal capacity while desorbing >99% of the boron adsorbed for three cycles of adsorption/desorption. Results indicated that a promising, reusable, and boron-selective biosorbent was successfully synthesized while utilizing olive pruning waste.Master Thesis Kinetics of Silica Polymerization at Various Conditions(01. Izmir Institute of Technology, 2022) Baba, Alper; Demir, Mustafa Muammer; Demir, Mustafa Muammer; Baba, Alper; 03.03. Department of Civil Engineering; 03.09. Department of Materials Science and Engineering; 03. Faculty of Engineering; 01. Izmir Institute of TechnologySilica is the most abundant element on Earth because the Earth's crust is composed mainly of metal silicates. The source of this silica is mainly volcanic rocks, which come to the surface through tectonic activity and are the primary source of heat for geothermal activity. The silica concentration in a geothermal fluid is higher than the solubility limit of natural waters, so scaling of (metal) silicates is often observed in geothermal operations. This situation has become critical for geothermal power plants. Since silicates have an insulating structure, they lead to a reduction in energy efficiency during fluid transport. The formation of silica-rich deposits should be understood to minimize the negative effects of the scaling. Briefly, silicic acid molecules in the reservoir system are condensed, and the monomeric silicic acid molecules bind to each other via covalent bonds. In the course of this reaction, dimers, tetramers and short oligomers are formed, and eventually a large polymeric silica network is formed. In the presence of metals, both the kinetics of polymerization and the structure of the network are inevitably affected. In this study, the presence of kinetic parameters (different salts such as FeCl3, MgCl2, AlCl3 and NaCl), the reaction process, the rate and the activation energy of silica polymerization at different temperatures between 25 and 90 °C were investigated. The yellow silicomolybdate method was used to determine the concentration of monomeric silica. The order of the polymerization reaction was given as 3. The polymerization occurs in the initial phase, in the first 40 minutes, where the activation energy was about 29.52 ± 2.28 kJ/mol and the rate constant was of the order of 4x10-8 mol-2∙L2∙s-1. The results also confirmed that pH has a stronger effect on the kinetics of silica polymerization than temperature. The neutral solution decreases rapidly, while the acidic solution has an induction phase in the first hour of polymerization. Different temperatures did not affect the polymerization rate as much as pH. At 25°C the experiment showed the fastest polymerization, but at 90°C the low concentration changed from the beginning. During all these experiments, no scaling of amorphous silica was observed, only the polymerization of silica.Master Thesis Simulation of Water Resources of Tahtalı-Seferihisar Sub-Basin Based on Weap Model(Izmir Institute of Technology, 2021) Elçi, Şebnem; Karahan, Sait Mutlu; Elçi, Şebnem; 03.03. Department of Civil Engineering; 01. Izmir Institute of Technology; 03. Faculty of EngineeringWater is a vital resource for humanity and nature, and the lack of water affects life in all areas. Today, problems such as the inability to protect the status of existing water resources and excessive water withdrawal cause the amount of water to decrease day by day. In addition, conditions such as urbanization and industrialization and the resulting population increase, deterioration of water quality due to chemicals used in agricultural activities, and climate change affect the availability of water resources negatively. In this study, a basin-based water management study was carried out by applying the "Integrated Water Resources Management" approach to the Tahtalı-Seferihisar Sub-Basin located in Turkey, where it is expected to experience water stress in the future. The hydrological (precipitation, flow, evaporation) data of the water resources that are important for the basin and İzmir (Tahtalı, Seferihisar, Ürkmez, and Kavakdere Dams) were used to predict the availability of water resources in the future using the WEAP (Water Evaluation and Planning System) program, and several possible scenarios for water demands/supplies were analyzed. Under these situations, the water budget balances expected to occur 2050 have been estimated. Basically, seven different scenarios were created to transfer possible future possibilities to the program: Reference Scenario, Best Case Scenario, Worst Case Scenario, Report Consumption Scenario, Return Flow Scenario, Population Projection Scenario and Various Forecast Scenario. The water balances that can be obtained under different conditions in each scenario were calculated and compared with each other.