Researcher:
Sezginel, Kutay Berk

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Master Student

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Kutay Berk

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Sezginel

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Sezginel, Kutay Berk

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Now showing 1 - 5 of 5
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    Publication
    Analysis of CH4 uptake over metal-organic frameworks using data-mining tools
    (Amer Chemical Soc, 2019) Gülsoy, Zeynep; Yıldırım, Ramazan; N/A; Department of Chemical and Biological Engineering; Department of Chemical and Biological Engineering; Department of Chemical and Biological Engineering; Sezginel, Kutay Berk; Uzun, Alper; Keskin, Seda; Master Student; Faculty Member; Faculty Member; Graduate School of Sciences and Engineering; College of Engineering; College of Engineering; N/A; 59917; 40548
    A database containing 2224 data points for CH4 storage or delivery in metal-organic frameworks (MOFs) was analyzed using machine-learning tools to extract knowledge for generalization. The database was first reviewed to observe the basic trends and patterns. It was then analyzed using decision trees and artificial neural networks (ANN) to extract hidden information and develop rules and heuristics for future studies. Five-fold cross validations were used in each analysis to test the validity of the models with data not seen before. Decision-tree analyses were carried out using six user-defined descriptors and two structural properties, separately. The crystal structure and the total degree of unsaturation were found to be the effective user-defined descriptors, whereas the pore volume and maximum pore diameter, as structural properties, were sufficient to determine the MOFs having high CH4-storage capacity. Moreover, a high pore volume is always required, as expected. In ANN analyses, models were also developed by using user-defined descriptors and structural properties separately. It was observed that the user-defined descriptors were not sufficient to describe the CH4-storage capacities of MOFs, whereas the structural properties in particular led to accurate CH4-storage predictions with an RMSE of 26.8 and an R-2 of 0.92 for testing.
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    Publication
    Prediction of methane storage performance of metal-organic frameworks
    (AIChE, 2014) N/A; Department of Chemical and Biological Engineering; Department of Chemical and Biological Engineering; Department of Chemical and Biological Engineering; Sezginel, Kutay Berk; Uzun, Alper; Keskin, Seda; Master Student; Faculty Member; Faculty Member; Koç University Tüpraş Energy Center (KUTEM) / Koç Üniversitesi Tüpraş Enerji Merkezi (KÜTEM); Graduate School of Sciences and Engineering; College of Engineering; College of Engineering; N/A; 59917; 40548
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    Publication
    Multivariable linear models of structural parameters to predict methane uptake in metal-organic frameworks
    (Elsevier, 2015) N/A; Department of Chemical and Biological Engineering; Department of Chemical and Biological Engineering; Department of Chemical and Biological Engineering; Sezginel, Kutay Berk; Uzun, Alper; Keskin, Seda; Master Student; Faculty Member; Faculty Member; Graduate School of Sciences and Engineering; College of Engineering; College of Engineering; N/A; 59917; 40548
    A key challenge preventing CH4-driven energy future is the lack of effective, economic and safe on-board CH4 storage systems. In this study, computational tools were utilized to examine CH4 storage capacity of metal-organic frameworks (MOFs) under practical operating conditions. Grand Canonical Monte Carlo (GCMC) simulations were performed to calculate CH4 uptake capacity of 45 MOFs. Results were confirmed with experimental data available in the literature. Motivated from the good agreement between experiments and simulations, a quantitative structure-property relationship (QSPR) analysis was performed. Making use of this analysis, multivariable linear models with one-, two-, three-, and four-variables that can accurately predict CH4 uptake of MOFs at room temperature and pressures ranging from 1 to 65 bar were developed. Model parameters were based on easily measurable/computable structural properties, such as pore volume, surface area, and density. Models that predict CH4 uptake at 5 and 35 bar were studied in detail to investigate the viability of reaching CH4 storage target for vehicular systems set by DOE. At both pressures the models with four variables outperformed other models at the same pressures, and void fraction (V-f) and isostetic heat of adsorption (Q(st)) were found to be the most significant parameters. In order for a material to exceed the DOE target of 0.5 g/g CH4 uptake at a storage pressure of 35 bar, the material should have high gravimetric surface area (S-g), reaching 6000 m(2)/g, void fraction (V-f), as high as 0.9, dominant pore diameter (DPD) approximately 30 angstrom, and Q(st) value around 30 KJ/mol. Results of this work reveal the structural properties controlling the CH4 storage capacity of MOFs. Such information can guide experimental studies to tune the MOFs in the way of designing new materials with desirable structural properties that will reach the storage targets. (C) 2014 Elsevier Ltd. All rights reserved.
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    Publication
    Tuning the gas separation performance of cubtc by ionic liquid incorporation
    (Amer Chemical Soc, 2016) N/A; Department of Chemical and Biological Engineering; Department of Chemical and Biological Engineering; Department of Chemical and Biological Engineering; Sezginel, Kutay Berk; Keskin, Seda; Uzun, Alper; Master Student; Faculty Member; Faculty Member; Graduate School of Sciences and Engineering; College of Engineering; College of Engineering; N/A; 40548; 59917
    The efficient separation of gases has industrial, economic, and environmental importance. Here, the gas separation performance of a metal organic framework (MOP) is enhanced by ionic liquid (IL) incorporation. One of the most commonly used ILs, 1-butyl-3-methylimidazolium tetrafluoroborate ([BMIM][BF4]), was incorporated into a commercially available MOF, CuBTC. Detailed characterization by combining spectroscopy with diffraction, electron microscopy, and thermal analysis confirmed that the structures were intact after incorporation. Adsorption isotherms of CH4, H-2, N-2, and CO2 in IL-incorporated CuBTC were experimentally measured and compared with those of pristine CuBTC. Consequently, ideal selectivities for CO2/ CH4, CO2/N-2, CO2/H-2, CH4/N-2, CH4/H-2, and N-2/H-2 separations were calculated. The results showed that the CH4 selectivity of CuBTC over CO2, H-2, and N-2 gases becomes at least 1.5 times higher than that of pristine CuBTC upon the incorporation of IL. For example, the CH4/H-2 selectivity of CuBTC increased from 26 to 56 at 0.2 bar when the IL loading was 30 wt %. These results show that the incorporation of ILs into MOFs can lead to unprecedented improvements in the gas separation performance of MOFs. The tunable physicochemical properties of ILs combined with a large number of possible MOF structures open up opportunities for the rational design of novel materials for meeting future energy challenges.
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    PublicationOpen Access
    Identifying highly selective MOFs for CH4/H2 separations using computational tools
    (American Chemical Society (ACS), 2015) Department of Chemical and Biological Engineering; Department of Chemical and Biological Engineering; Başdoğan, Yasemin; Sezginel, Kutay Berk; Keskin, Seda; College of Engineering; N/A; N/A; 40548
    The large number of metal organic frameworks (MOFs) represents both an opportunity and a challenge for identification of materials exhibiting promising properties in gas separations. We used molecular simulations to screen 250 different MOP structures in order to examine their adsorption-based CH4/H-2 separation performances. Adsorption selectivity, working capacity, sorbent selection parameter, and regenerability of MOFs were calculated and compared with those of traditional nanoporous materials. The accuracy of simple models that can predict adsorption selectivity of MOFs based on structural properties of materials was discussed. With the use of molecular dynamics, gas diffusivities were computed in the MOFs which were identified as the top performing materials for adsorption-based CH4/H-2 separation. Membrane selectivities of these MOFs were predicted to discuss kinetic separation performances of materials. Results showed that there is a significant number of MOFs that exhibit extraordinarily large adsorption-based and membrane-based CH4/H-2 selectivities compared to well-known nanoporous materials such as zeolites. Using MOFs as adsorbents rather than membranes would be more efficient in CH4/H-2 separation.