Yazar "Uğur Nigiz, Filiz" seçeneğine göre listele
Listeleniyor 1 - 7 / 7
Sayfa Başına Sonuç
Sıralama seçenekleri
Öğe Baca Gazından Karbondioksit Ayırmak Için Farklı Metal Organik Kafes-Polimer Nanokompozit Membran Üretimi(2023) Uğur Nigiz, FilizBu çalışmada baca gazı karışımlarından karbondioksitin ayrılması için hem camsı hem de kauçuksu polimerik membranların hazırlanması ve bu membranlarla gaz ayırımı çalışması yapılması hedeflenmiştir. Membranların karbondioksit seçiciliğinin arttırılması için membran içine metal organik kafes (MOF) eklenmiş bu sayede hem mekanik dayanımları hem de gaz ayırma performansları arttırılmıştır. Proje kapsamında farklı metal organik kafesler farklı zincir bağlayıcılar ile denenmiş en uygun olanlarının kafes boyutları nispeten küçük olan MIL 140A ve MIL 140B olduğu görülmüştür. Her malzeme membrana %1-4 oranında eklenmiştir. Sonuç olarak üretilen membranlarla projede hedeflendiği gibi 100 Barrer üzeri geçirgenlik ve 20 üzeri CO2/N2 seçicilikleri elde edilmiştir. PVA matrisinde, MIL 140A oranı sıfırdan %4'e çıkarken CO2 geçirgenliği 92 Barrer den 171 Barrer?e seçicilik ise 41,4'den 54,1'e artmıştır. MIL 140B oranı sıfırdan %4'e çıkarken CO2 geçirgenliği 92 Barrer den 179 Barrer'e seçicilik ise 41,4'den 58,7'e artmıştır. Pebax 2533 matrisinde, MIL 140A oranı sıfırdan %4 değerine arttıkça, CO2/N2 seçicilik değeri 19,8 değerinden 38,1 değerine artarken geçirgenlik değeri de 285 Barrer'den 372 Barrer'e artış göstermiştir. MIL 140B arttıkça CO2/N2 seçicilik değeri 19,8 değerinden 33,4 değerine artarken geçirgenlik değeri de 285 Barrer'den 431 Barrer'e artış göstermiştir. Pebax 1657 Martisinde, MIL 140A oranı sıfırdan %4 değerine arttıkça, CO2/N2 seçicilik değeri 52,4 değerinden 81,3 değerine geçirgenlik değeri de 76 Barrer'den 102 Barrer'e artış göstermiştir. MIL 140B oranı %4 değerine arttıkça, CO2/N2 seçicilik değeri 52,4 değerinden 79,2 değerine geçirgenlik değeri de 76 Barrer'den 111 Barrer'e artış göstermiştir.Öğe Comparative study on use of pervaporation membrane reactor for lauric acid – Methanol esterification(Elsevier, 2021) Uğur Nigiz, Filizn this study, an esterification reaction between lauric acid and methanol was performed in an inert and catalytic pervaporation membrane reactor (PVMR) and the conversion results were compared. Reactions were also per- formed in a batch reactor, demonstrating the advantage of membrane reactors over conventional reactors. Phosphotungstic acid (PTA), a strongly heteropolyacid, was used as a catalyst. An inert and PTA coated polyvinyl alcohol membranes were synthesized for use in the inert and catalytic membrane reactor, respectively. Effects of catalyst concentration (from 1 wt% to 2 wt%), methanol/lauric acid molar ratio (from 2 to 6), and temperature (from 50 ◦C to 65 ◦C) on lauric acid conversion and membrane separation performance were studied. Throughout the study, the effect of membrane separation performance on acid conversion was clearly demonstrated. Under all operating conditions, the acid conversion results obtained in inert and catalytic PVMR were higher than in batch reactors. When the methanol/lauric acid molar ratio was 6, the temperature was 65 ◦C, and the catalyst ratio was 2 wt%, a conversion of 80.7% was obtained in the batch reactor, while 98.9% and 97.5% of conversions were obtained in the inert and catalytic membrane reactor, respectively. Based on these results, it has been relatively demonstrated that inert and catalytic PVMR systems are efficient in producing fatty acid methyl ester.Öğe Electricity production from dairy wastewater using phosphotungstic acid- Poly(vinylidene fluoride) Membrane supported microbial fuel cell(Elsevier Ltd, 2025) Özyörü, Zeynep İrem; Uğur Nigiz, FilizMicrobial fuel cells (MFCs) are device to use waste materials to product electricity. This is of great importance for both waste management and energy production. In MFCs, proton exchange membranes (PEM) are frequently used. Therefore, electricity production and efficiency directly depend on the hydrogen transfer performance of these membranes. In this study, phosphotungstic acid (PTA) doped nanofiber polyvinyldifloride (PVDF) membranes were prepared and the electricity production potential from dairy industry wastewater was examined. The morphological property, the chemical structure, mechanical strength, and the antimicrobial property of membranes were investigated. Water uptake, proton conductivity, and the ion exchange capacity of membranes were also studied. Finally, the electricity production potential of membranes in dual-chamber MFC system was investigated. As a result, it was observed that the increasing PTA ratio reduced the fiber diameter from micro-scale to nano-scale. The PTA edition improved the mechanical strength from 5.67 MPa to 8.86 Mpa, the proton conductivity from 0.56 mS/cm to 1.61 mS/cm. The power generation of the cell increased almost more than 3 times to 8.8 mW/m2. It was also observed that PTA additive significantly enhanced the antimicrobial effect of the membrane.Öğe Fabrication of Zr MOF-doped polyvinylidene fluoride membranes and testing in H-type microbial fuel cell(Elsevier Ltd, 2024) Uğur Nigiz, Filiz; Akel, MustafaMicrobial fuel cells (MFCs) are an important tool that generates electricity from waste biomass. Polymer electron membrane supported dual-chamber MFCs are one of the most tested microbial fuel cells. The most important factor affecting performance in this system is the proton transfer capability of the membrane. In this study, zirconia based metal organic frameworks (Zr-MOF) doped porous membranes were produced, characterized and used in dual chamber (H-type) MFC to generate electricity from animal manure (Cow manure). The effects of MOF ratio on membrane's physical, chemical properties, and on the cell performance were investigated. The incorporation of MOF into the PVDF matrix improved the water retention property of the membrane. The Zr-MOF addition increased the mechanical strength from 0.55 MPa to 1.52 MPa. The cation exchange capacity increased from 1.04 mmol/g to 2.41 mmol/g. It significantly increased the cell electricity production from 0.186V to 0.49V. The power density values are obtained as 5.02 and 13.8 mW/m2 with the pristine and Zr-MOF(4)-PVDF membranes, respectively.Öğe Halloysite Nanotube doped poly lactic acid membrane preparation and seawater desalination(Elsevier, 2023) Uğur Nigiz, Filiz; Karakoca, BetülHalloysite nanotube (Hal) is a natural alumina silicate clay mineral. Hal is used in polymer composites for many reasons such as excellent physical and chemical properties, good miscibility, mechanical strength, antimicrobial properties, and cheapness. It is an important material used in water separation, especially due to its internal and external ionic structure hollow tubular structure. In this study, halloysite was used as a filler in polylactic acid polymer to produce a nanocomposite membrane for seawater purification. The morphological, physical, and chemical structures of the Hal filled, and unfilled membranes were investigated. The effect of HAL content (from 0% to 5% by weight), feed temperature (from 40 degrees C to 60 degrees C), NaCl concentration (from 2 wt% to 6 wt%), and the downstream pressure (from 10 mbar to 30 mbar) on the desalination performance were investigated as a function of flux and salt rejection. Hal improved the hydrophilicity, stability, mechanical strength, and the desalination performance of PLA membrane, significantly. The results showed that the highest desalination performance was achieved by 5 wt% of Hal-loaded membrane. The highest flux of 13.14 kg/m2.h was obtained accompanied by a rejection of 99.95%. The membrane was also used to purify seawater, and it was found that the permeate's ion concentrations met drinking water standards. The nanocomposite membrane was experimented over 100 h of testing, and no decrease in flux or salt rejection was seen.Öğe Photocatalytic activity of TiO2-Cu-metal-organic framework (MOF)(Bulgarska Akademiya na Naukite, 2023) Katırcı, Ayşenur; Kibar, M.E.; Uğur Nigiz, FilizThe accumulation of greenhouse gases including carbon dioxide (CO2) in the atmosphere has greatly increased with industrialization and creates serious problems on our environment such as global warming, melting of glaciers, sea level rise, and extinction of species. One of the solutions is to reduce the level of CO2. CO2 conversion can be achieved in a sustainable and environmentally safe way by a light-based photocatalytic method. In this study, a titanium dioxide doped copper metal organic framework (TiO2/Cu-MOF-NH2) based photocatalyst was prepared for the photocatalytic reduction of CO2. MOFs are effective photocatalysts after surface modification, structuring with other semiconductors, and doping with metal nanoparticles. The activity of the photocatalyst (TiO2/CuMOF-NH2) was determined by means of synthetic dye reduction reaction. In order to determine the effect of TiO2 on the MOF structure, characterization of TiO2/Cu-MOF-NH2 and Cu-MOF-NH2 was done. The photocatalysts were characterized using Fourier transform infrared spectroscopy, scanning electron microscopy, and X-ray diffraction tests. As a result, 17% of adsorption and 31.7% adsorption-photocatalysis were achieved by TiO2/Cu-MOF-NH2 photocatalysis.Öğe Production of natural zeolite-filled recycled PVDF filters and their application for gray water treatment(Royal Soc Chemistry, 2025) Katırcı, Ayşenur; Kahraman, Seniyecan; Uğur Nigiz, FilizIn this study, clinoptilolite (Clp)-doped poly(vinylidene fluoride) (PVDF) membranes (1-4 wt%) were prepared using an electrospinning method. Further, filtration tests on the simulated gray water components were investigated. Methylene blue (MB), linear alkyl benzene sulfonate (LAS), oil (soybean oil), and microplastic (MP) filtration were performed. MB filtration with the PVDF membrane resulted in over 99% of MB rejection. Oil rejection with the PVDF membrane without Clp was observed to be 95%, while the addition of Clp increased the oil rejection to over 99%. It was observed that LAS rejection increased as the Clp content increased. MP rejection using PVDF-based membranes was 100%. Considering all the test results, the membrane containing 3 wt% Clp showed the best performance, and the process parameters and rejection efficiencies were determined through experimental optimization. Synthetic gray water analyses included the chemical oxygen demand (COD), pH, conductivity, and total dissolved solids (TDS). COD rejection was 63.1%, while turbidity rejection was 97.2%.
