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.Chitosan

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Now showing 1 - 3 of 3
  • Master Thesis
    Adsorbent Synthesis for the Recovery of Lithium Water Resources
    (01. Izmir Institute of Technology, 2022) Yüksel Özşen, Aslı; Yüksel Özşen, Aslı; Yüksel Özşen, Aslı; 03.02. Department of Chemical Engineering; 03. Faculty of Engineering; 01. Izmir Institute of Technology
    Lithium is a crucial mineral for the 21st century due to its utilization in a wide range of industries. Lithium demand will increase because of car battery developments and the necessity for power storage. Investigating alternative strategies for resource recovery is the only way to fulfill this unexpected rise properly and sustainably in demand. Adsorption has been discovered to have some technological advantages over other methods. It is considerably less expensive, lacks the chemical resistance present in membranes, lacks the significant electrical demand of electrochemical approaches, as well as the restricted selectivity and challenges in integration into commercial processes. Lithium manganese oxides, also known as lithium ion-sieves, are adsorbents for lithium extraction that have remarkably high selectivity, high adsorption capacity, minimal toxicity, good chemical stability and cheap cost. They are one of the most promising inorganic adsorbents. This research emphasized on the recovery of lithium from water resources through the use of lithium manganese oxide, which were synthesized in laboratory. They were transformed into spherical beads by adding chitosan, followed by crosslinking these beads with epichlorohydrin to increase their adsorption yield, stability, and reusability. Characterization techniques such as SEM, XRD and BET were applied on the adsorbents. Results shows that the adsorbents distributed uniformly, the adsorbent powder was mesoporous, and from the adsorption studies it was found that the adsorbent worked much better in alkaline conditions such as pH 12, optimum adsorbent dosage estimated as 4 g/L and the equilibrium time measured as 10 hours. From the desorption study approximately 95% of Li desorbed for the first cycle, after the second cycle the adsorbent efficiency started to decrease.
  • Master Thesis
    Preparation and Characterization of Polymer Based Composite Nanospheres for Bone Infection Prevention
    (Izmir Institute of Technology, 2018) Kımna, Ceren; Tıhmınlıoğlu, Funda; Tıhmınlıoğlu, Funda; 03.02. Department of Chemical Engineering; 03. Faculty of Engineering; 01. Izmir Institute of Technology
    Currently, bone tissue engineering applications comprise the development of smart materials that can induce tissue regeneration meanwhile supporting the defect site of the body. Despite of the advancements, inflammation is still a serious problem that threatens human health at the post-implantation period. To overcome potential inflammations, antibiotic therapy is commonly employed in clinical trials. However, antibiotic therapy causes some side effects such as ototoxicity and nephrotoxicity, especially when applied in high doses. Therefore, local drug delivery systems play a vital role in bone disorders due to the elimination of disadvantages introduced by conventional methods. In the presented study, it was aimed to develop chitosan-based composite nanospheres as a controlled drug delivery system against bone infections. Accordingly, chitosan and montmorillonite nanoclay was homogenized with microfluidizer and electrosprayed to obtain spherical nanoparticles. The optimum electrospraying conditions were investigated using response surface methodology. Vancomycin and Gentamicin antibiotics were incorporated in the polymeric matrix to provide controlled release at the defect region to overcome inflammations after implantation. The prepared nanospheres were characterized in terms of morphology, hydrodynamic size distribution, surface charge, drug encapsulation efficiency and release profiles. The dominant drug release mechanism was determined by empirical mathematic models. Drug loaded nanospheres have been successfully produced with a size range of 180-350 nm. High encapsulation efficiency was achieved (80-95%) with a controlled drug release up to 30 days. Fickian diffusion was found as the main mechanism in drug delivery from spherical CS/MMT nanocomposites. The in vitro release medium of nanospheres showed strong antimicrobial activity against gram-positive S. aureus and gram-negative E. coli bacteria. Furthermore, it was found that the nanospheres did not show any cytotoxic effect to 3T3 and SaOS-2 cell lines. These results demonstrated that the prepared nanospheres can be a promising option for bone infection prevention.
  • Master Thesis
    Development of a Hybrid Sorbent Composed of Natural Materials for the Removal of Arsenic From Waters
    (Izmir Institute of Technology, 2014) Yılmaz, Dilek; Sofuoğlu, Sait Cemil; Sofuoğlu, Sait Cemil; 03.07. Department of Environmental Engineering; 03. Faculty of Engineering; 01. Izmir Institute of Technology
    A novel sorbent has been developed by immobilizing chitosan onto pumice for As(V) sorption from waters. In order to ensure its functionality, sorption performance was determined by measuring As concentrations in water using hydride generation atomic absorption spectrometry. The success of the immobilization was checked with characterization techniques as scanning electron microscopy, thermal gravimetric analysis, and elemental analysis. Points of zero charges were determined with potentiometric mass titration. Batch type equilibration studies showed that the sorbent can be employed at a wide pH range resulting in quantitative sorption (>90%) at pH 3.0-7.0, and greater than 70% sorption at pH>8.0. These results demonstrate the advantage of immobilizing chitosan onto pumice, because, under the same conditions, pumice displays <20% sorption towards As(V) whereas chitosan gives approximately 90% sorption but only at pH 3.0. The validity of the method was verified through the analysis of ultra-pure, bottled drinking, and tap water samples spiked with arsenate; the respective sorption percentages of 93.2 (±0.7), 89.0 (±1.0), and 80.9 (±1.3) were obtained by batch type equilibration. The sorbent was applied in a column for the spiked samples of ultra-pure and tap water. Similar sorption percentages (60% at the 18th fraction) were obtained for ultra-pure water whereas the methodology gave more efficient results for tap water (90% at the 20th fraction) demonstrating the potential of the sorbent for an efficient water treatment system. Arsenic sorption was also examined in the presence of common interfering ions resulting in competing effects of PO43- and NO3- on As(V) adsorption.