Research Project: Cu-BTC Metal Organik Yapının Metan Depolama Performansının ve Dayanıklılığının İyonik Sıvılar Kullanılarak İyileştirilmesi
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Contributors
Funders
ID
TB.00221
Authors
Uzun, Alper
Faculty Member
Publications
Tuning the gas separation performance of cubtc by ionic liquid incorporation
(American Chemical Society, 2016) Keskin, Seda; Sezginel, Kutay Berk; Uzun, Alper; Department of Chemical and Biological Engineering; KUTEM (Koç University Tüpraş Energy Center); Yes; College of Engineering; Research Center
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.
Structural factors determining thermal stability limits of ionic liquid/mof composites: imidazolium ionic liquids combined with cuBTC and ZIF-8
(American Chemical Society, 2019) Keskin, Seda; Nozari, Vahid; Uzun, Alper; Zeeshan, Muhammad; Department of Chemical and Biological Engineering; KUYTAM (Koç University Surface Science and Technology Center); KUTEM (Koç University Tüpraş Energy Center); Yes; College of Engineering; Research Center
Twenty-nine different imidazolium ionic liquids (ILs) were combined with two different metal-organic frameworks (MOFs), ZIF-8 and CuBTC, and the resulting IL/MOF composites were characterized in detail by combining X-ray diffraction (XRD), scanning electron microscopy (SEM), Brunauer-Emmett-Teller (BET), and Fourier transform infrared (FTIR) spectroscopy. Characterization data illustrated that MOFs remained structurally intact upon combining them with ILs. Thermogravimetric analysis performed on IL/MOF composites showed that most of the composites have lower thermal stabilities compared to the bulk ILs and pristine MOFs, whereas composites with ILs having a functional group in their anions showed thermal stability limits higher than those of bulk ILs. The derivative onset temperatures representing the maximum tolerable temperatures of the composites were analyzed based on the structural differences in MOFs and ILs, such as the changes in the alkyl chain length, methylation on the C2 site, and functionalization of the cation and the size/electronic changes on the anion. Data illustrated that the maximum tolerable temperatures of IL/MOF composites decrease with an increase in the alkyl chain length on the IL's imidazolium ring. Substitution of the alkyl group with functionalized groups in the IL's imidazolium ring also led to a decrease in the maximum tolerable temperatures of the composites. VVhereas, fluorination of the anion resulted in an increase in the thermal stability limits of the corresponding IL/MOF composites. Furthermore, ILs having a dicyanamide, acetate, and phosphate anion also showed an increase in their maximum tolerable temperatures when combined with CuBTC compared to their bulk counterparts. Moreover, simple structural descriptors for each cation and anion were defined by means of the density functional theory (DFT) calculations and used in the quantitative structure-property relationship (QSPR) analysis to correlate the maximum tolerable temperatures of IL/MOF composites to the IL's cation and anion structure. Results presented in this study will provide a guideline for the selection of proper IL-MOF pairs according to the application temperature of IL/MOF composites in various fields.
Doubling CO2/N2 separation performance of CuBTC by incorporation of 1-n-ethyl-3-methylimidazolium diethyl phosphate
(Elsevier, 2021) Gülbalkan, Hasan Can; Haşlak, Zeynep Pınar; Keskin, Seda; Uzun, Alper; Zeeshan, Muhammad; Department of Chemical and Biological Engineering; Graduate School of Sciences and Engineering; KUTEM (Koç University Tüpraş Energy Center); KUYTAM (Koç University Surface Science and Technology Center); Yes; College of Engineering; GRADUATE SCHOOL OF SCIENCES AND ENGINEERING; Research Center
1-ethyl-3-methylimidazolium diethyl phosphate ([EMIM][DEP]) was incorporated into copper benzene-1,3,5-tricarboxylate, CuBTC. Consequences of molecular interactions on the CO2 separation performance of CuBTC were investigated. Scanning electron microscopy and X-ray diffraction results showed that the surface morphology and crystal structure of CuBTC remained intact upon the incorporation of the ionic liquid (IL); and the results of thermogravimetric analysis and infrared spectroscopy indicated the presence of interactions between the anion of the IL and the open metal sites of CuBTC. Gas adsorption measurements for the pristine CuBTC and IL-incorporated CuBTC were performed at 25 °C in a pressure range of 0.1–1 bar. Data showed that ideal CO2/CH4 and CO2/N2 selectivities of IL-incorporated CuBTC were 1.6- and 2.4-times higher compared to those of the pristine CuBTC at 0.01 bar, respectively. Moreover, for the CO2/CH4:50/50 and CO2/N2:15/85 mixtures, the corresponding selectivities were improved by more than 1.5- and 1.9-times compared to that of pristine CuBTC at 0.01 bar, respectively.
Composites of porous materials with ionic liquids: synthesis, characterization, applications, and beyond
(Elsevier, 2022) Alsuhile, Ala Abdulalem Abdo Moqbel; Çağlayan, Hatice Pelin; Durak, Özce; Gülbalkan, Hasan Can; Habib, Nitasha; Haşlak, Zeynep Pınar; Keskin, Seda; Öztulum, Samira Fatma Kurtoğlu; Uzun, Alper; Zeeshan, Muhammad; Zhao, Yuxin; Department of Chemical and Biological Engineering; Graduate School of Sciences and Engineering; KUTEM (Koç University Tüpraş Energy Center); KUYTAM (Koç University Surface Science and Technology Center); Yes; College of Engineering; GRADUATE SCHOOL OF SCIENCES AND ENGINEERING; Research Center
Modification of the physicochemical properties of porous materials by using ionic liquids (ILs) has been widely studied for various applications. The combined advantages of ILs and porous materials provide great potential in gas adsorption and separation, catalysis, liquid-phase adsorption and separation, and ionic conductivity owing to the superior performances of the hybrid composites. In this review, we aimed to provide a perspective on the evolution of IL/porous material composites as a research field by discussing several different types of porous materials, including metal organic frameworks (MOFs), covalent organic frameworks (COFs), zeolites, and carbonaceous-materials. The main challenges and opportunities in synthesis methods, characterization techniques, applications, and future opportunities of IL/porous materials are discussed in detail to create a road map for the area. Future advances of the field addressed in this review will provide in-depth insights into the design and development of these novel hybrid materials and their replacement with conventional materials.
Analysis of CH4 uptake over metal-organic frameworks using data-mining tools
(American Chemical Society, 2019) Keskin, Seda; Sezginel, Kutay Berk; Uzun, Alper; Gülsoy, Zeynep; Yıldırım, Ramazan; Department of Chemical and Biological Engineering; KUTEM (Koç University Tüpraş Energy Center); KUYTAM (Koç University Surface Science and Technology Center); Yes; College of Engineering; Research Center
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.
