Master Degree / Yüksek Lisans Tezleri

Permanent URI for this collectionhttps://hdl.handle.net/11147/3008

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Department: search.filters.department.Thesis (Master)--İzmir Institute of Technology, Chemical EngineeringSubject: search.filters.subject.Composite materials

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Now showing 1 - 3 of 3
  • Master Thesis
    Synthesis of Ni and Zn Based Organic Frameworks as Photocatalyst
    (Izmir Institute of Technology, 2019) Dikmen, Merve; Özkan, Seher Fehime; Çakıcıoğlu Özkan, Seher Fehime; 03.02. Department of Chemical Engineering; 03. Faculty of Engineering; 01. Izmir Institute of Technology
    Nickel (Ni) and zinc (Zn) based organic frameworks were synthesized on the synthetic zeolite (5A and 13X), natural zeolite mineral clinoptilolite, -Alumina. Initially the zeolite surface was modified or seeded with metal organic framework (MOF). MOF-zeolite composite materials were characterized with XRD, SEM and ATR-IR to understand whether surface processes was achieved successfully or not. Additionally, band gap energies were evaluated to understand these composite materials were used as photocatalyst. Surface modification with APTES was not affect surface of the zeolites. In spite of that seeding created a layer on the surface of zeolite. Nickel based organic framework was coated onto the surface of modified 5A surface. Hydrothermal ZIF8 (ZIF8(1)) and solvothermal ZIF8 (ZIF8(2)) were synthesized successfully as MOF crystals. Besides ZIF8(2) was coated onto the surface of natural zeolite. Additionally, ZIF8/CuBTC sample were synthesized, seeded and coated onto the surface of natural zeolite. Band gap energies of the MOFs and composite materials were calculated with Tauc plot. Results showed that UV light can be used as light source for photocatalytic reactions of these photocatalysts. Also increasing photocatalyst amount increased dye degredation under UV light.
  • Master Thesis
    Preparation of Natural Zeolite Supported Tio2 Composites for Removal of Terephthalic Acid
    (Izmir Institute of Technology, 2014) Deliismail, Özgün; Deliismail, Özgün; Özkan, Seher Fehime; Çakicioğlu Özkan, Seher Fehime; Helvacı, Şerife Şeref; 03.02. Department of Chemical Engineering; 03. Faculty of Engineering; 01. Izmir Institute of Technology
    This study focuses on the preparation of natural zeolite supported TiO2 composites for the removal of model pollutant, terepththalic acid (TPA) via sorption. Natural zeolite was purified and used to prepare natural zeolite supported TiO2 adsorbents. Prior to sorption, the adsorbents were characterized by Scanning Electron Microscopy, Volumetric Adsorption Instrument, X-ray Diffractometer, Fourier Transformer Infrared, Induced Coupled Plasma Atomic Emmision Spectroscopy, and Thermal Gravimetric Analyzer. It was deduced that natural zeolite was clinoptilolite rich low (Ca) silicate. The sorption studies of TPA on adsorbents were applied in dark conditions at room temperature by altering adsorbent amount (0.2-1.5 g/l) and initial TPA concentration (20-60 ppm). It was observed that the amount of adsorbed TPA per unit mass of adsorbent decreased with increasing adsorbent amount, and sorption percent was unchanged (about 72%). This can be explained by the affinity of adsorbents to water molecules more than TPA molecules. Much more number of TPA molecules was allocated on the clinoptilolite than TiO2 composites. Sorption mechanism was identified by fitting the kinetic data to diffusion (Weber-Morris model, intraparticle/external diffusion) and reaction models (First order and pseudo second order model). First order reaction model was well correlated to experimental data for sorption process. Comparing pore size of the adsorbents to molecular size of TPA indicates that main contribution to intraparticle diffusion was the intercrystalline diffusion. Intraparticle diffusion was not the sole rate-limiting step due to the existence of external resistance. Biot and Weber-Morris calculations corroborated these results. In the future, photocatalytic performance of these adsorbents will also be tested.
  • Master Thesis
    Preparation and Characterization of Polypropylene Cellulose Composites
    (Izmir Institute of Technology, 2004) Atikler, Ulaş; Tıhmınlıoğlu, Funda; Tıhmınlıoğlu, Funda; 03.02. Department of Chemical Engineering; 03. Faculty of Engineering; 01. Izmir Institute of Technology
    In recent years, much effort has been driven to replace glass fibers, which were used to reinforce thermoplastic composites, with natural fibers. In this study, three natural fibers, namely cellulose (CE), sawdust (SD) and wheat straw (WS) were employed as reinforcement to polypropylene (PP) polymer matrix. The most important problem encountered with natural fiber/PP composites is the inherent incompatibility between hydrophilic natural fibers and hydrophobic PP matrix, thus coupling agents were employed to alter incompatibility between fiber and matrix. Coupling agents enhance interfacial interactions by chemical and physical bonding between fiber and matrix. Surface treatment of natural fibers were carried out with two kinds of silanes;(3-aminopropyl)-triethoxysilane (AS) and methacriloxy propyl trimethoxy silane (MS), and maleic anhydride grafted polypropylene (MAPP). Silane coupling agents were agitated in aqueous ethanol solution in the presence of fibers at weight percents of 0.5, 1 and 2.5 with respect to fiber weight. MAPP was compounded during melt mixing of fiber and PP at weight percents of 2.5, 5 and 10 with respect to PP weight PP/fiber composites were prepared in a rheomixer equipped with two rotor blades and adjustable temperature, mixing rate and mixing time. Composites were prepared at 185 oC, 50 rpm mixing rate and 10 minutes mixing time. Torque values of each composite formulation were recorded with respect to time to determine changes in rheological properties of composites. It was found that increase in fiber loading increases stabilization torque of composites. Mechanical properties of PP/fiber composites were significantly enhanced byemployment of coupling agents and MAPP was found to be the most effective coupling agent. Mechanical properties of SD composites were found to exhibit the best performance compared to C and WS. Extent of interfacial interactions were evaluated with Pukanszky and Nielsen model and superior performance of MAPP in enhancing interfacial interactions was confirmed by these two models. Optimum conditions for coupling agents were found to be 1 wt % for silane coupling agents and 5 wt % for MAPP. It was found that water sorption and void fraction of the composites decreased with employment of coupling agents. Among the coupling agents, MAPP exhibited the best performance in decreasing water sorption and void fraction of composites confirming results of mechanical tests. Scanning electron micrographs (SEM) used to illustrate the effect of coupling agents on adhesion between fiber and matrix and fracture modes of the composites. In addition, FTIR analysis revealed the decrease in hydrophilicity of fibers with silane treatment and new bond formations with employment of MAPP.