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Öğe A novel and clean technique for the one-pot production of green chemical ?-valerolactone from furfural using bifunctional H3PW12O4/UiO-66 catalyst: Pervaporation membrane reactor(Elsevier Sci Ltd, 2024) Mutlu, Bade; Unal, Buse; Unlu, DeryaThis study focuses on the synthesis of gamma-valerolactone (GVL) from furfural using a bifunctional H3PW12O4UiO-66 catalyst. The membrane was prepared using PBI polymer. H3PW12O4-UiO-66 catalysts with different amounts of H3PW12O4 were synthesized. The catalytic activity of these synthesized catalysts was investigated in pervaporation membrane reactor to obtain GVL from furfural and the catalyst containing 2 g of H3PW12O4 was identified as the optimum catalyst. After determining the optimum catalyst, the effect of temperature, molar feed ratio, and catalyst concentration on the reaction and separation performance was investigated. The optimum values were determined as 90 degrees C, molar feed ratio 10 and 6 g/L catalyst concentration by evaluating both reaction and separation performance. The performance of the pervaporation membrane reactor (PVMR) was compared with a batch reactor operated under the same conditions. In the batch reactor operating at 90 degrees C, molar feed ratio of 10, and 6 g/L catalyst concentration, a 65% furfural conversion and 51% GVL yield were obtained, whereas the PVMR achieved 100% furfural conversion and 94.21% GVL yield. This comparison demonstrates the improved efficiency of the PVMR in increasing conversion and yield compared to the traditional batch reactor. The obtained conversion and yield values under the investigated operating conditions highlight the proposed process as a promising alternative for the production of GVL from furfural.Öğe Biochar-based ZrO2 doped adsorbents for removal of methyl orange dye from textile wastewater(Inderscience Enterprises Ltd, 2025) Kurcin, Huriye Ceren; Aslan, Sevgi Kemec; Unlu, DeryaThe industrial revolution has caused production and consumption rates to increase, which has consequently led to a rise in water usage. However, this case has also led to a rise in wastewater generation, posing a significant threat to the environment. Organic and inorganic substances present in wastewater mix with clean water sources, causing pollution in the environment. Particularly, compounds originating from industrial dyeing processes in textiles can be toxic to aquatic ecosystems. In this study, the removal of methyl orange in wastewater has been investigated by using ZrO2-modified grape and olive waste-derived bio-adsorbents. The properties of the bio-adsorbents were determined through FTIR, XRD, BET, and SEM analyses, while the removal of methyl orange was evaluated using UV spectrophotometry. The influence of adsorbent dosage and pH on dye removal was examined. The results indicate that olive-based bio-adsorbents are effective in removing up to 88% of dye from water.Öğe Caustic in textile processes and environmentally responsible solutions: a mini-review(Springer Heidelberg, 2025) Musaoglu, Nur; Unlu, DeryaThe textile industry is a sector that encompasses the production and processing of textile products, one of the important necessities of human life. The textile market has high growth potential and faces significant sustainability challenges. The fashion and textile industry is experiencing significant attention and growth, with projections estimating a compound annual growth rate (CAGR) of 4.4% by 2028. Textile processes consume large amounts of water (55 L per kg fabric of water) and energy (8-20 kWh/kg), while chemicals released into wastewater cause environmental impacts. Therefore, environmentally friendly, and efficient production methods are being explored. Caustic is one of the chemicals that play an important role in textile processing however, the use of caustic causes environmental pollution. The mercerization process in the textile industry consumes 170-350 g/kg fabric of caustic soda. It is therefore important to investigate caustic recovery and alternative chemicals that can be used instead. Caustic recovery aims to recover and reuse caustic from wastewater. This method can be cost-effective while reducing environmental impacts. Another method is to evaluate alternative chemicals that can be used instead of caustic. Enzymes play a major role in studies of alternative chemicals. Enzymes are an environmentally friendly option that can replace chemicals used in textile processes. The use of enzymes can lead to softer touch and more efficient results in textile production. However, enzymes have some limitations such as cost and stability issues. Therefore, developments and research in enzyme technology are ongoing. Overall, the textile industry faces considerable challenges related to sustainability and efficiency. This study aims to recommend several key strategies for the recovery of caustic in textile dyehouse wastewater and alternative chemicals that can be used instead of caustic. This paper presents a comprehensive study on caustic management practices in textile dyeing plants, emphasizing strategies to minimize wastewater generation.Öğe CO2-Enhanced Synthesis of Trimethyl Borate from Ulexite: Innovations in Pervaporation Separation(Amer Chemical Soc, 2025) Ozekmekci, Mehtap; Copur, Mehmet; Unlu, DeryaThe primary objective of this research is to enhance a novel method for the eco-friendly production of trimethyl borate (TMB) from ulexite ore by utilizing carbon dioxide. Notably, CO2, a major greenhouse gas, is converted into thermodynamically stable CaCO3 following TMB synthesis. TMB, a significant organo-boron chemical, has a wide range of industrial applications. In this study, the trimethyl borate production process consists of three main steps: reaction, distillation, and pervaporation. Trimethyl borate was synthesized through the reaction of ulexite with methanol in a high-pressure reactor under a CO2 atmosphere. The obtained liquid product was subjected to distillation to produce the TMB-methanol azeotrope. Following the distillation process, the separation of TMB from the azeotrope mixture was achieved by utilizing pervaporation. The TMB-methanol azeotrope and pure TMB were characterized and confirmed by using Fourier transform infrared (FTIR) spectroscopy and gas chromatography (GC). In this research, hydroxyethyl cellulose (HEC) and polyvinylpyrrolidone (PVP) were used as the membrane materials. Blend membranes were prepared by the solution casting evaporation method. The morphologies of the membranes were characterized by FTIR spectroscopy, thermogravimetric analysis (TGA), X-ray diffraction (XRD), scanning electron microscopy (SEM), and contact angle assessment. The pervaporation performance of all blend membranes was evaluated for the separation of the TMB-methanol azeotrope. The effects of the operating temperature, methanol feed concentration, and PVP ratios on separation performance were investigated. The results demonstrated that a TMB purity of 97.71 wt % was achieved when the PVP-HEC-2 membrane was utilized in pervaporation. In conclusion, this study introduces an innovative and environmentally friendly process for producing valuable chemicals, highlighting its potential for industrial applications.Öğe Dehydration of industrial isopropanol wastewater by pervaporation using carboxy methyl cellulose and graphene oxide hybrid membranes(Bulgarska Akademiya na Naukite, 2024) Unlu, DeryaIsopropanol (IPA) is widely used as an industrial solvent, cleaning agent, and in producing chemicals, fuels and medical products. Many applications require anhydrous IPA without water. IPA-containing wastewaters are generated from its production and uses. Dewatering and recycling IPA from these waste streams is important for both economic and environmental reasons. IPA and water form an azeotropic mixture, making conventional dehydration methods like distillation and extraction challenging. Membrane-based processes such as pervaporation offer advantages over these processes, as it can break azeotropes while requiring lower energy and having a smaller footprint. In this study, hybrid membrane was used to dehydration of industrial isopropanol wastewater by pervaporation. The study focused on preparing hybrid membranes for pervaporation dehydration by incorporating graphene oxide into a carboxy methyl cellulose matrix. This integration of graphene oxide led to an enhancement in the dehydration separation performance of the hybrid membranes. Additionally, the research systematically characterized and evaluated the impact of graphene oxide concentration, operation temperature, and feed IPA concentration on various properties such as hydrophilicity, swelling, and dehydration. These analyses aimed to understand the influence of these factors on the overall performance and properties of the hybrid membranes. Optimum process conditions have been determined and under these conditions, water flux 4.7 kg/m2h and separation factor value of 128 were obtained. The study's findings pave the way for the future development of carboxy methyl cellulose (CMC) based hybrid membranes for implementation in pervaporative dehydration processes. © 2024 Bulgarian Academy of Sciences, Union of Chemists in Bulgaria.Öğe Efficient and Sustainable Bleaching of Cotton and Cotton/Polyester Fabric Using Alternative Chemicals(Korean Fiber Soc, 2025) Musaoglu, Nur; Unlu, DeryaIn textile wet processing, caustic soda is widely used in the pre-treatment stage, serving as the primary chemical for bleaching and mercerization processes. The conventional use of caustic soda leads to issues, such as high water consumption and wastewater pollution. Therefore, this study explores alternative chemicals that could replace caustic soda while minimizing environmental harm. The research was conducted on 100% cotton (CO) and cotton-polyester (CO-PES)-blended fabrics. The chemicals used in this study include caustic soda, gelatin, acetic acid, oxalic acid, and ethanol. For bleaching, oxalic acid was found to be the chemical that provided the best wettability in both fabric types. The use of sodium hydroxide gave the most effective results for high whiteness in both CO and CO-PES fabrics. When color retention was evaluated, the bleaching process using gelatin gave the closest result to the reference fabric in terms of color retention. Oxalic acid made the biggest difference in color retention. In conclusion, this study highlights the importance of using environmentally friendly alternatives in the textile industry and demonstrates the potential of chemicals that can replace caustic soda. The findings contribute to the adoption of sustainable practices in textile production and represent an important step in reducing environmental impact.Öğe High-efficiency pervaporative separation of fuel bioadditive methylal from methanol by poly(vinyl alcohol)/poly(vinylpyrrolidone) blend membrane(Springer Heidelberg, 2023) Unlu, DeryaMethylal is a fuel bioadditive. The purification of methylal has been conducted by the pervaporation process. The purification of methylal from the reaction mixture is required to use the methylal as a fuel additive for diesel or biodiesel. In this study, poly(vinyl alcohol) (PVA) and poly(vinylpyrrolidone) (PVP) polymers were used and the blend membrane was prepared by using these polymers. The prepared PVA/PVP blend membranes have been utilized for the separation of methylal/methanol binary mixtures and methylal/methanol/water ternary mixtures in a pervaporation process. Membranes were characterized by Scanning electron microscopy (SEM), Fourier transform infrared spectroscopy (FTIR), Thermogravimetric analysis (TGA), contact angle measurements and X-ray Diffraction Analysis (XRD). Pervaporation tests were performed at different feed concentrations, operation temperatures and PVP loading ratios. The best separation performance was obtained at 10 wt. % of PVP loaded membrane. Optimum process conditions were determined as 30 degrees C of operation temperature and 5 wt. % of feed methanol concentration. Under these conditions, methanol flux and methanol selectivity values were 0.21 kg/m(2) h and 98.01, respectively. Approximately, 99% of purity methylal has been achieved in the retentate stream by removing the methanol. The innovation of this study is to develop an alternative method, which is of high purity and low energy consumption according to the literature, for the purification of methylal biofuels.Öğe Improved biobutanol recovery through mixed-matrix PVDF membrane with hydrophobic MAF-6 as filler(Bulgarska Akademiya na Naukite, 2025) Ozdemir, Ruveyda; Unlu, DeryaIn this study, enhancing the hydrophobicity of the membrane by using MAF-6 was considered an effective strategy to improve the performance of organophilic pervaporation (PV) membranes. This was achieved by incorporating superhydrophobic MAF-6 into polyvinylidene fluoride (PVDF) polymer to create mixed matrix membranes (MMMs). Various characterization techniques were employed to assess the morphologies of the MAF-6 nanocrystals and the membranes, including BET and SEM. The pervaporation experiments involving butanol/water mixtures demonstrated that the MMMs exhibited enhanced flux and separation factors compared to the PVDF pristine membrane. The optimal flux achieved was 1.35 g/m² h, with a separation factor of 16.7. This enhancement in performance was attributed to the hydrophilicity and high porosity of MAF-6, which effectively overcame the trade-off effect usually observed in such membranes. © 2025 Bulgarian Academy of Sciences, Union of Chemists in Bulgaria.Öğe Innovative Process for the Purification of Green Aviation Fuel Additive “Dimethoxymethane”: Pervaporation(Springer Nature, 2024) Unlu, DeryaThe aim of this study is purification of aviation fuel additive “dimethoxymethane” by using pervaporation process. Polyetherimide (PEI) membrane was utilized for the purification of dimethoxymethane from dimethoxymethane/methanol mixtures. Membranes were characterized by scanning electron microscopy (SEM) and Fourier transform infrared spectroscopy (FTIR). Purification tests were performed in different feed methanol concentration and operation temperature. Methanol selectivity value was obtained as infinite. The results obtained show that high purity dimethoxymethane green aviation fuel additive can be achieved by pervaporation process. © The Author(s), under exclusive license to Springer Nature Switzerland AG 2024.Öğe Investigation of the efficiency of hydrogen production from sodium borohydride hydrolysis with a novel biobased catalyst Bio-MOF(Pergamon-Elsevier Science Ltd, 2025) Ozdemir, Ruveyda; Unlu, DeryaThe global scenario with increasing energy demand and depleting fossil fuel resources has propelled the exploration of renewable energy sources. Hydrogen energy, seen as a promising alternative, offers a clean and sustainable option for energy production. While electrolysis is a common method for hydrogen production, sodium borohydride (NaBH4) presents a unique pathway where hydrogen can be readily utilized in fuel cells without the need for electrolysis. The key component in hydrogen production from NaBH4 is the catalyst and noble metal catalysts with high catalytic activity are generally used. Despite their high catalytic activity, the application of noble metal catalysts in large-scale production of hydrogen is limited by their high cost, low abundance and environmental impact. In this study, efforts have been carried out to improvement alternative catalyst with lower cost and environmental friendly. For this purpose, succinic acid-based metal-organic framework catalyst has been synthesized. Bio-MOF is made from bio ligand from natural products as succinic acid (C4H6O4). The hydrothermal method using water as solvent is used for synthesis. The Bio-MOF catalyst was characterized by FT-IR, TGA, SEM, XRD, and BET analyzes. The surface area is calculated as 158.702 m2/g with pore volume of 0.2389 cm3/g from BET analysis. The amounts of catalyst (100-200 mg) and NaBH4 (50-400 mg) and various temperatures (30-70 degrees C) were optimized. The optimum reaction conditions were determined as 150 mg of catalyst amount, operation temperature of 60 degrees C and 400 mg NaBH4 of amount. The highest hydrogen production volume was found 300 mL under these conditions. The activation energy was calculated 79.67 kJ/ mol. These features make Bio-MOF an effective heterogeneous catalyst for H2 production from NaBH4.Öğe Lithium recovery from lithium/magnesium containing waters with biodegradable chitosan based EDTA doped adsorbent(Taylor & Francis Inc, 2025) Dagdeviren, Rumeysa; Sevinc, Rumeysa; Unlu, DeryaThe shift from conventional fossil fuel vehicles to electric (and hybrid electric) vehicles plays a crucial role in reducing CO2 emissions to prevent global warming. Lithium-ion batteries have become a primary choice for electric vehicles due to their high energy density and light weight compared to other battery types. In this study, an adsorbent was developed to adsorb Mg2+ in solutions containing Li/Mg binary component, thus obtaining lithium in concentrated form. EDTA-chitosan adsorbent based on biodegradable polymer chitosan was synthesized as adsorbent. Adsorbents were characterized using XRD, FTIR, BET and SEM analysis. The effects of adsorbent amount, pH, Li/Mg feed ratio on Mg2+ removal percentage and separation factor were investigated. The optimum separation conditions are determined as pH = 4.5, adsorbent amount of 0.3 g, Li/Mg feed ratio of 1:20. Under these optimum conditions, 99.36% of magnesium removal percentage and 141.28 of Li/Mg separation factor were obtained.Öğe Microstructural, thermal and ablative properties of TiB2 modified carbon fiber reinforced resorcinol formaldehyde composites for thermal protection of aerospace vehicle(Wiley, 2025) Aras, Sefa; Cavusoglu, Ferda Civan; Yilmaz, Nevin Gamze Karsli; Unlu, DeryaAblative polymeric composites were fabricated using vacuum impregnation and hot press molding techniques. The composites consisted of needled carbon fiber felt as the reinforcing material and resorcinol-formaldehyde (RR) or boron-modified resorcinol-formaldehyde resin (RRB) as the matrix. Different weight percentages of titanium diboride (TiB2) were incorporated as a filler. The ablation mechanisms of the composites were derived from SEM-EDS, XPS, and XRD analysis of char layers formed after exposure to an oxyacetylene flame. The composites displayed excellent thermal insulation properties during the oxyacetylene test. The back surface temperatures ranged from 24.8 to 26.8 degrees C, indicating minimal heat penetration through the composites. This composite demonstrated a linear ablation rate (LAR) of 0.0053 mm/sec, a mass ablation rate (MAR) of 0.0195 g/sec, and a charring rate (CR) of 0.0543 mm/sec. During ablation, the low LAR, MAR, and CR values of C-RRB-T composites confirm that these composites are promising for thermal protection system applications in aerospace.Highlights Resorcinol formaldehyde matrix was modified with boron and filler TiB2. Composites were fabricated using vacuum impregnation and hot press molding. The thermal stability and char yields of the composites increased with TiB2. The addition of TiB2 to the C-RRB composite improved the ablation properties.Öğe Pervaporative desalination by phosphomolybdic acid/PVA hybrid membrane(Bulgarska Akademiya na Naukite, 2023) Unlu, DeryaWater is indeed a precious natural resource and essential for all living organisms. Despite the Earth's abundant water resources, only a small portion is freshwater suitable for drinking and utilization. This accounts for approximately 0.3% of the Earth's total water capacity, equivalent to about 105 thousand km3. As a result, desalination has emerged as a viable solution to produce clean water by converting seawater, which is an almost limitless supply. Among the various desalination processes, pervaporation (PV) has attracted significant attention due to its numerous advantages, including low energy consumption, simplicity in operation, low cost, and high separation performance within a short period. The current study proposes the application of pervaporation for desalination purposes. Specifically, a hydrophilic polymer, polyvinyl alcohol (PVA), is chosen for membrane synthesis in the desalination process. Polymeric membranes are comparatively easier to produce and more cost-effective than other types of membranes. However, polymeric membranes tend to exhibit a swelling behavior, resulting in high flux and low selectivity. To address this challenge, recent advancements have led to the development of hybrid membranes, known as organic-inorganic composite membranes. In this study, phosphomolybdic acid (PMA) is chosen as an additive material. The effects of the amount of phosphomolybdic acid, salt concentration, and operation temperature on desalination performance are examined. Optimal operating conditions are determined, resulting in a salt rejection rate of 99.99% and a flux value of 2.45 kg/m2 h. These findings demonstrate the potential of the proposed membrane system for efficient desalination applications. © 2023 Bulgarian Academy of Sciences, Union of Chemists in Bulgaria.Öğe Polyvinyl pyrrolidone-chitosan blend membrane for pervaporation separation of trimethyl boratemethanol mixture(Springer, 2025) Ozekmekci, Mehtap; Copur, Mehmet; Unlu, DeryaTrimethyl borate (TMB) is an essential chemical for applications ranging from organic synthesis to borohydride production and requires efficient separation from methanol for optimal utilization. This study investigates the pervaporation performance of blend membranes composed of different ratios of chitosan (CS) and polyvinyl pyrrolidone (PVP) to improve the separation of TMB/methanol mixtures through pervaporation. The structural morphology, thermal properties, and crystalline nature of these membranes were comprehensively characterized using Fourier transform infrared spectroscopy, thermogravimetric analysis, contact angle measurements, scanning electron microscopy, and X-ray diffraction analysis. Pervaporation experiments were conducted by varying feed compositions, operating temperatures, and PVP ratios. The results demonstrated that increasing PVP content has a significant effect on permeation flux. The best conditions were obtained at 45 degrees C of operation temperature and 75% (by wt) TMB-25% (by wt) methanol mixture by utilizing a PVP-CS-2 membrane, recording flux value of 335.44 g/m2 h. Additionally, PVP-CS-1 and PVP-CS-2 blend membranes were subjected to a crosslinking process to evaluate their separation performance. The crosslinked PVP-CS-1 membrane showed a good performance, with a selectivity value of 146.37. Additionally, the crosslinked PVP-CS-2 membrane exhibited remarkable stability 5 run experiments, indicating strong chemical and mechanical endurance.Öğe Synergistic effect of graphene oxide and MOF-235 for efficient hydrogen generation from sodium borohydride hydrolysis(Pergamon-Elsevier Science Ltd, 2026) Ozdemir, Ruveyda; Unlu, DeryaThe global rise in energy demand and depletion of fossil fuels have intensified the search for clean and renewable energy sources. Hydrogen is a promising energy carrier due to its high energy density and environmentally friendly nature. Among hydrogen production routes, sodium borohydride (NaBH4) hydrolysis offers an efficient and controllable process for on-demand hydrogen generation. However, the development of cost-effective and sustainable catalysts remains a major challenge. In this study, a MOF-235@GO composite catalyst was successfully synthesized via a low-temperature hydrothermal method. The catalyst was characterized by XRD, FTIR, TGA, SEM-EDS, XPS and BET analyses. The effects of catalyst amount, NaBH4 concentration, NaOH concentration and temperature on hydrogen generation were systematically investigated. The optimum conditions were determined as 100 mg catalyst, 200 mg NaBH4, 0.25 M NaOH and 80 degrees C, yielding 490 mL of hydrogen. The reaction followed zero-order kinetics with an activation energy of 61.83 kJ/mol. These findings highlight the potential of MOF-235@GO as an efficient and environmentally friendly catalyst for sustainable hydrogen production from NaBH4 hydrolysis.Öğe Synthesis, Characterization, and Thermal Pyrolysis Mechanism of Resorcinol-Formaldehyde Resin-Containing Phenylboronic Acid(Wiley-V C H Verlag Gmbh, 2024) Aras, Sefa; Cavusoglu, Ferda Civan; Unlu, DeryaIn the present study, a resin is synthesized from resorcinol and formaldehyde in the presence of phenylboronic acid. Properties of resins such as free formaldehyde content, total solid content, density, gelation time, viscosity are determined. The chemical structure of the resorcinol-formaldehyde resin and the resorcinol-formaldehyde resin containing phenylboronic acid is confirmed by Fourier transform infrared spectroscopy (FTIR), nuclear magnetic resonance spectroscopy, X-ray photoelectron spectroscopy (XPS), X-ray diffraction (XRD), and scanning electron microscopy (SEM). The thermal stability and curing behaviors of the polymers are investigated by thermogravimetric analysis (TGA) and differential scanning calorimetry, respectively. Modification of the resorcinol-formaldehyde resin with a boron source, phenylboronic acid results in a certain increase in thermal stability with a higher residual weight. The 6% PBA loaded polymer has the highest thermal efficiency, so the thermal behavior of it is investigated by curing at different temperatures. The 80 degrees C/4 h curing method is the most reasonable for energy savings. In differential scanning calorimetry (DSC) analysis, a 6 wt% PBA loading ratio was determined as the optimum value according to the energy requirements. In this study, a resin is synthesized from resorcinol and formaldehyde in the presence of phenylboronic acid. The 80 degrees C/4 h curing method is the most reasonable for energy savings. While the char residue yield of pure RR resin was 47.9%, the char residue yield of RRB6 resin increased to 54.9%.image (c) 2024 WILEY-VCH GmbHÖğe Water Desalination by Pervaporation Using MIL-101(Cr) and MIL-101(Cr)@GODoped PVA Hybrid Membranes(Springer Int Publ Ag, 2023) Unlu, DeryaIn this study, MIL-101(Cr) and MIL-101(Cr)@GO were produced and added to the poly (vinyl alcohol) (PVA) membrane for the manufacture of hybrid membranes to use in pervaporative desalination. The MIL-101(Cr) and MIL-101(Cr)@GO additives were identified using Fourier-transform infrared spectroscopy (FTIR) and X-ray powder diffraction (XRD). The hybrid membranes were analyzed by using FTIR (chemical bond structure), XRD (crystallinity and amorphous phase), scanning electron microscope (SEM) (morphologic structure), thermogravimetric analysis (TGA) (thermal features), and contact angle (hydrophility). The effects of MIL-101(Cr) and MIL-101 (Cr)@GO content in the PVA membrane, feed sodium chloride (NaCl) concentration, and operation temperature were assessed for the flux and salt rejection. The addition of MIL-101(Cr) and MIL-101(Cr)@GO to the PVA membrane improved the purification performance in pervaporative desalination applications. The durability of the hybrid membrane for desalination was studied. The optimal loading ratios for MIL-101(Cr) and MIL-101(Cr)@GO were specified as 4 wt% MIL-101(Cr) and 4 wt% MIL-101(Cr)@GO, respectively. Optimum operation parameters were achieved at 60 degrees C of temperature and a 4 wt% of feed NaCl concentration for both hybrid membranes. Hybrid membranes (MIL-101(Cr)@GO doping) exhibited excellent desalination success with salt rejections of 99.99% and fluxes of 9.7 kg/m(2) h. It was also seen that the hybrid membranes preserved their separation performance during 10 cycles.Öğe Yakıt biyokatkı maddesi ve yeşil solvent metilalin UiO-66 katkılı PEI nanokompozit membran kullanılarak pervaporasyon prosesi ile saflaştırılması(2023) Unlu, DeryaBu çalışmada, metilal/metanol ikili karışımlarının pervaporasyon prosesi ile saflaştırılması için UiO-66 katkılı PEI nanokompozit membranlar hazırlanmıştır. Membranlar, Taramalı elektron mikroskobu (SEM), Fourier dönüşümlü kızılötesi spektroskopisi (FTIR) ve Termogravimetrik analiz (TGA) ile karakterize edilmiştir. Pervaporasyon testleri farklı operasyon sıcaklıklarında, besleme metanol konsantrasyonunda, UiO-66 yükleme oranında ve membran kalınlığında gerçekleştirilmiştir. Optimum çalışma koşulları 30oC çalışma sıcaklığı, ağırlıkça %6 besleme metanol konsantrasyonu, ağırlıkça %0.5 UiO-66 katkılı PEI nanokompozit membran ve 50 ?m membran kalınlığı olarak belirlenmiştir. Bu koşullar altında akı ve metanol seçicilik değerleri sırasıyla 1.48 kg/m2.h ve 80126 olarak elde edilmiştir. Elde edilen sonuçlar, pervaporasyon işlemi ile yüksek saflıkta metilal yakıt biyokatkı maddesi ve yeşil solvent elde edilebileceğini göstermektedir.Öğe Yalıtım Malzemesi Poliüretan Köpüğün Alev Direncini Arttıracak Reçine Katkılı Poliüretan Kompozit Sentezi(2024) Karamahmutoğlu, Sinem; Kozan, Merve; Aras, Sefa; Unlu, DeryaRijit poliüretan köpükler (RPUF) en popüler, enerji verimi yüksek ve çok yönlü yalıtım malzemeleri arasında yer almaktadır. RPUF, özellikle binalarda verimli ve konforlu yalıtım malzemesi olarak kullanımının yanısıra enerji maliyetlerini de önemli ölçüde azaltmaktadır. RPUF’ların, alevlenebilir olması uygulama alanlarını ciddi şekilde kısıtlamaktadır. Kömür verimi ve alev dirençleri arttırıldığında kısıtlı uygulama alanları da ortadan kaldırılabilir. Resorsinol-formaldehit (RF) reçinesi yüksek kömür verimi ve alev direnci ile ön plana çıkmaktadır. Bu çalışmada da düşük kömür verimli ve alev dirençli RPUF’un hazırlanma aşamasında, yüksek kömür verimine ve oldukça düşük alevlenebilirliğe sahip RF reçinesi dahil edilmiştir. İlk olarak RF reçinesi sentezlenmiştir. İkinci aşamada poliol karışımı ve poliizosiyanat birleştirilerek karıştırılıp RPUF’lar hazırlanmıştır. Son aşamada poliol karışımı ve poliizosiyanat ile karıştırılmış RF reçinesi birleştirilerek karıştırılıp rijit poliüretan-resorsinol-formaldehit kompozitleri hazırlanmıştır. Hazırlanan kompozit köpük numuneleri için termogravimetrik analiz (TGA), Fourier dönüşümlü kızılötesi spektroskopisi (FT-IR), Taramalı elektron mikroskobu (SEM), Görünür yoğunluk ve dikey yanma testi uygulanmıştır. RPUF’larda ağırlıkça RF içeriğindeki artışla birlikte köpüklerin yanma dayanımı artmıştır. Reçinesiz poliüretan köpüğü ilk 10 saniyede tamamen yanarken, %20 RF reçinesi içeren köpüğün (RF20-RPUF) doğrusal yanma hızı reçinesiz poliüretan köpüğe göre %91.33 daha düşüktür.
