Master Degree / Yüksek Lisans Tezleri

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

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2016 - 20185

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Subject: search.filters.subject.MembraneWoS Q: search.filters.wosQuartile.N/A

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Now showing 1 - 5 of 5
  • Master Thesis
    Preparation and Characterization of Antifouling Nanofiltration Membranes From a Responsive Pentablock Copolymer
    (Izmir Institute of Technology, 2018) Çağlar, Nağahan; Alsoy Altınkaya, Sacide
    The most substantial factor restricting the extensive application of membrane processes is the fouling problem resulting from the deposition of solutes in water on the surface or within the pores of membranes. The frequently used chemical washing procedure to eliminate the fouling issue causes environmental pollution and shortens the membrane life. In order to overcome these disadvantages, the development of membranes possessing low fouling potential is needed. In recent years, the stimuliresponsive polymers have received attention for developing membranes possessing low fouling potential. The antifouling property of these membranes is controlled through the change in their conformation and hydrophilic/hydrophobic characteristics as a response to change in external stimuli such as pH, temperature and ionic strength. The aim of this study was to design antifouling nanofiltration membranes (NF) using a pentablock copolymer which consists of temperature responsive Pluronic F127 (PEO-b-PPO-b- PEO) in the middle block and pH responsive poly(N,N-(diethylamino)ethyl methacrylate) (PDEAEM) in the end blocks. Effects of pH and temperature responsiveness on the membrane fouling were investigated. Fouling tendencies of the membranes were evaluated by using Bovine Serum Albumin (BSA), Alginate (ALG) as organic foulant and Escherichia coli (E.coli) as biological foulant. NF membranes were characterized by scanning electron microscope (SEM), contact angle and zeta potential measurements. It was demonstrated that pentablock copolymer coated membranes displayed antifouling resistance by changing filtration pH and temperature.
  • Master Thesis
    Investigation of the Performances of Ceramic Micro/Ultrafiltration Membranes in Stable Oil in Water Emulsion Purification
    (Izmir Institute of Technology, 2018) Çetin, Pınar; Çiftçioğlu, Muhsin
    Increasing water scarcity is an important threat to the whole world. The use of too much water during the production processes and the insufficient level of reuse of this water and the increasing quantities of oil containing waste generated in many industrial activities cause dangerous consequences for the environment. Highly concentrated oil-in-water emulsions are very harmful for aquatic life, soil, atmosphere and human health. Traditional treatment methods are not effective in the removal of emulsified oil droplets which have less than 20 μm of droplet size. Ceramic micro/ultrafiltration membranes have been explored and developed in recent years due to their superior advantages in oil containing water treatment/purification. The aim of this MSc study was to produce tubular ceramic micro/ultrafiltration membranes for the removal of oil from stable oil in water emulsions. The prepared emulsions with about 5-6 μm of droplet sizes were fed to the crossflow filtration system and the effects of experimental parameters such as transmembrane pressure (TMP), crossflow velocity (CFV) and temperature on membrane performance/permeate flux was investigated. Titania, zirconia and neodymium doped polymeric sols were prepared and coated on the MF layer in order to investigate coating/surface modification on probable permeate flux enhancement and separation ability of the membrane. The reduction of the total suspended solid (TSS) and turbidity were determined as 100 %. A stable permeate flux with a lower extent of membrane fouling and concentration polarization was obtained with 1 m/s of CFV and 2 bar of TMP.
  • Master Thesis
    Preparation of Asymmetric Ti̇o2 Based Nano/Ultrafiltration Membranes for Wastewater Treatment
    (Izmir Institute of Technology, 2017) Odabaşı, İklima; Çiftçioğlu, Muhsin
    Fresh water scarcity have been the most fundamental problem in the world and is already affecting mankind and human activities. This problem forced an increasing effort in the reuse of wastewater originating from municipal, agricultural, and industrial activities. The textile industry demands large amounts of water and produces large quantities of wastewater. Adsorption, filtration, ozonation and photocatalysis techniques are currently used for wastewater treatment and safe discharge to the environment. Although membrane filtration necessitates a high initial setup cost, it has a high potential and may cause significant cost savings through the reuse of water and salts. The membrane based technologies are widely accepted to be the best method when compared with the currently available technologies for wastewater treatment. Extruded tubular alumina supports were coated by stable colloidal sols and polymeric sols prepared by using sol-gel based techniques for the formation of selective micro/ultra/nanofiltration layers in this work. Textile wastewater treatment (with and without pre-treatment) and membrane fouling analysis was conducted. The performances of the membranes were determined through the characterization of permeates by spectrophotometer. The reduction of colors (Pt-Co, m-1), turbidity and suspended solids content were about 99%, 100% and 100%, respectively. The incorporation of a coagulation stage by using Al2(SO4)3 followed by a successive filtration reduced the membrane/irreversible fouling levels in the MF/UF membranes significantly. The Pt-Co 455 values of permeates were determined to be in the 15-260 range which are below the discharge criteria bringing the possibility of the reuse of some of these permeates.
  • Master Thesis
    Development of Thin Film Composite Nanofiltration Membranes With Layer by Layer Polyelectrolyte Deposition
    (Izmir Institute of Technology, 2017) Tekinalp, Önder; Alsoy Altınkaya, Sacide
    Nanofiltration (NF) membranes are usually prepared in thin film composite (TFC) structure through polymerization of various monomers or coating of previously synthesized polymer on porous support membranes. Layer by layer (LbL) deposition of polyelectrolytes on a porous support is a facile and convenient method for the sake of producing NF membranes. This study intends to manufacture TFC NF membrane via alternating polyelectrolyte deposition with limited number of layers on polysulfone/sulfonated polyethersulfone (PSF/SPES) porous support membrane. Polyethyleneimine (PEI) and alginate (ALG) were chosen as polyelectrolyte pairs. The support membranes with different pore sizes were prepared via nonsolvent induced phase inversion method by changing compositions and thickness of casting solution as well as composition of coagulation bath. The polyelectrolytes were deposited dynamically in a dead end filtration module at 1 bar. The influences of supporting electrolyte, polyelectrolyte pH and concentration as well as type of coating method on the membrane performances were investigated. The membranes were characterized by SEM, AFM, staining, and contact angle measurements. Stability and fouling tendency of produced membranes were determined. It was demonstrated that NF membrane (83% PEG1000 rejection) with a high flux (14 L/m2.h.bar) can be manufactured by depositing only a single layer of PEI. Further deposition of ALG on PEI-coated membrane resulted in water permeability of 15.5±0.3 L/m2.h.bar with 89.1±0.6% PEG1000 rejection by adjusting PSF:SPES ratio to 4:1.
  • Master Thesis
    Glucose Biosensor Applicatiın of Electrospun Polyvinyl Alacohol (pva) Fibers
    (Izmir Institute of Technology, 2016) Berber, Emine; Demir, Mustafa Muammer; Yıldız, Ümit Hakan
    Electrospinning is a simple and versatile technique for the fabrication of polymeric nanofibrous membranes with high surface to volume ratio. Besides the large surface area of the fibrous membranes, their dimensional stability and flexibility allows the immobilization of biomolecules on to the nanofiber surfaces. Therefore, electrospun nanofibers have been extensively used in enzyme electrodes. This thesis examines the glucose biosensor application of electrospun polyvinyl alcohol (PVA) nanofibers – carbon nanotube (CNT) nanocomposite membranes. By manipulating the structural design and the composition of the nanocomposite membranes, glucose sensing efficiency of the five different enzyme electrodes a) Glucose oxidase (GOx) immobilized PVA electrospun electrode, b) Glucose oxidase (GOx) immobilized PVA electrospun electrode containing multi-walled carbon nanotube (MWCNT), c) Glucose oxidase (GOx) immobilized PVA electrospun electrode containing Poly(diallyldimethylammonium chloride) (PDDA) functionalized multi-walled carbon nanotube (MWCNT) d) Glucose oxidase (GOx) immobilized PVA electrospun electrode containing Poly(diallyldimethylammonium chloride) (PDDA) functionalized single-walled carbon nanotube (SWCNT), e) Interfacially cross-linked PVA electrospun electrode containing Poly(diallyldimethylammonium chloride) (PDDA) functionalized multi-walled carbon nanotube (MWCNT) were comperatively studied. PVA electrospun nanofibers were fabricated by using electrospinning technique. Morphology and average diameter of the fibers were characterized by using Scanning Electron Microscopy (SEM). Average diameter for the neat PVA electrospun fibers were 115 nm. Carbon nanotubes were oxidatively functionalized by acid treatment and addition of functional groups after acid treatment was proved by using Raman Spectroscopy. Glucose sensing activities of the electrodes were amperometrically measured at an applied voltage -0.5 V (vs. Ag/AgCl) in 0.1M phosphate buffer solution (PBS pH 7). Glucose detection sensitivies of the electrodes were calculated as 19.6, 27.7, 67.5, 44.4, 4.0 μA mM-1cm-2 respectively.