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    Improved biobutanol recovery through mixed-matrix PVDF membrane with hydrophobic MAF-6 as filler
    (Bulgarska Akademiya na Naukite, 2025) Ozdemir, Ruveyda; Unlu, Derya
    In 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.
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    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, Derya
    The 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.
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    Synergistic effect of graphene oxide and MOF-235 for efficient hydrogen generation from sodium borohydride hydrolysis
    (Pergamon-Elsevier Science Ltd, 2026) Ozdemir, Ruveyda; Unlu, Derya
    The 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.