Researcher:
Keskin, Seda

Profile Picture
ORCID

OrgUnit Logo
Organizational Unit

Job Title

Faculty Member

First Name

Seda

Last Name

Keskin

Name

Name Variants

Keskin, Seda

Email Address

Birth Date

Filters

2010 - 20191032020 - 202461

Advanced Search

Filter by

Settings

Researcher Of Publications: search.filters.isAuthorOfPublication.8cf1edd5-df6e-424d-82cd-98cb2a079858

Search Results

Now showing 1 - 10 of 164
  • Placeholder
    PublicationMetadata only
    IL-modified MOF-177 filler boosts the CO2/N2 selectivity of Pebax membrane
    (Elsevier, 2024) Department of Chemical and Biological Engineering; Department of Chemical and Biological Engineering; Habib, Nitasha; Tarhanlı, İlayda; Şenses, Erkan; Keskin, Seda; Uzun, Alper; Koç University Tüpraş Energy Center (KUTEM) / Koç Üniversitesi Tüpraş Enerji Merkezi (KÜTEM); Koç University Surface Science and Technology Center (KUYTAM) / Koç Üniversitesi Yüzey Teknolojileri Araştırmaları Merkezi (KUYTAM); Koç University Boron and Advanced Materials Application and Research Center (KUBAM) / Koç Üniversitesi Bor ve İleri Malzemeler Uygulama ve Araştırma Merkezi (KUBAM); Graduate School of Sciences and Engineering; College of Engineering
    Mixed matrix membranes (MMMs) having ionic liquid (IL) modified metal-organic frameworks (MOF) as fillers present a broad potential for enhancing the separation properties of the polymers. Here, we incorporated an IL, 1butyl-1-methyl-pyrrolidinium tricyanomethanide [BMPyr][TCM], into MOF-177 and used the corresponding composite as filler in Pebax polymer to fabricate IL/MOF-177/Pebax MMMs at different filler loadings. These MMMs along with those prepared by using pristine MOF-177 as a filler were then tested for CO2/N2 separation by measuring their CO2 and N2 permeabilities at 35 degrees C and 1 bar. The [BMPyr][TCM]/MOF-177/Pebax MMM having 10 wt.% filler loading showed remarkable improvements in both CO2 permeability (137 f 2.0 Barrer) and CO2/N2 selectivity (622 f 105) compared to the neat Pebax membrane having corresponding performance values of 98.0 f 2.0 Barrer and 64.5 f 6.0, respectively. This simultaneous improvement in both CO2 permeability and CO2/N2 selectivity breaks the trade-off limitation of polymer membranes. Besides, the MMMs having 10 and 15 wt.% loadings of fillers were located well above the updated Robeson's upper bound, demonstrating the great promise of [BMPyr][TCM]/MOF-177/Pebax MMMs for CO2/N2 separation.
  • Placeholder
    PublicationMetadata only
    High-throughput computational screening of MOF adsorbents for efficient propane capture from air and natural gas mixtures
    (AIP Publishing, 2024) Department of Chemical and Biological Engineering; Department of Chemical and Biological Engineering; Erçakır, Göktuğ; Aksu, Gökhan Önder; Keskin, Seda; Graduate School of Sciences and Engineering; College of Engineering
    In this study, we used a high-throughput computational screening approach to examine the potential of metal-organic frameworks (MOFs) for capturing propane (C3H8) from different gas mixtures. We focused on Quantum MOF (QMOF) database composed of both synthesized and hypothetical MOFs and performed Grand Canonical Monte Carlo (GCMC) simulations to compute C3H8/N2/O2/Ar and C3H8/C2H6/CH4 mixture adsorption properties of MOFs. The separation of C3H8 from air mixture and the simultaneous separation of C3H8 and C2H6 from CH4 were studied for six different adsorption-based processes at various temperatures and pressures, including vacuum-swing adsorption (VSA), pressure-swing adsorption (PSA), vacuum-temperature swing adsorption (VTSA), and pressure-temperature swing adsorption (PTSA). The results of molecular simulations were used to evaluate the MOF adsorbents and the type of separation processes based on selectivity, working capacity, adsorbent performance score, and regenerability. Our results showed that VTSA is the most effective process since many MOFs offer high regenerability (>90%) combined with high C3H8 selectivity (>7 x 103) and high C2H6 + C3H8 selectivity (>100) for C3H8 capture from air and natural gas mixtures, respectively. Analysis of the top MOFs revealed that materials with narrow pores (<10 angstrom) and low porosities (<0.7), having aromatic ring linkers, alumina or zinc metal nodes, typically exhibit a superior C3H8 separation performance. The top MOFs were shown to outperform commercial zeolite, MFI for C3H8 capture from air, and several well-known MOFs for C3H8 capture from natural gas stream. These results will direct the experimental efforts to the most efficient C3H8 capture processes by providing key molecular insights into selecting the most useful adsorbents.
  • Placeholder
    PublicationMetadata only
    Reactive capture and electrochemical conversion of CO2 with ionic liquids and deep eutectic solvents
    (Royal Society of Chemistry, 2024) Dongare, Saudagar; Zeeshan, Muhammad; Dikki, Ruth; Coskun, Oguz Kagan; Munoz, Miguel; Banerjee, Avishek; Gautam, Manu; Ross, R. Dominic; Stanley, Jared S.; Brower, Rowan S.; Muchharla, Baleeswaraiah; Sacci, Robert L.; Velazquez, Jesus M.; Kumar, Bijandra; Yang, Jenny Y.; Hahn, Christopher; Morales-Guio, Carlos G. Spurgeon, Joshua M.; Gurkan, Burcu; Department of Chemical and Biological Engineering; Department of Chemical and Biological Engineering; Aydoğdu, Ahmet Safa; Öztulum, Samira Fatma Kurtoğlu; Uzun, Alper; Keskin, Seda; Koç University Tüpraş Energy Center (KUTEM) / Koç Üniversitesi Tüpraş Enerji Merkezi (KÜTEM); Koç University Surface Science and Technology Center (KUYTAM) / Koç Üniversitesi Yüzey Teknolojileri Araştırmaları Merkezi (KUYTAM); Graduate School of Sciences and Engineering; College of Engineering
    Ionic liquids (ILs) and deep eutectic solvents (DESs) have tremendous potential for reactive capture and conversion (RCC) of CO2 due to their wide electrochemical stability window, low volatility, and high CO2 solubility. There is environmental and economic interest in the direct utilization of the captured CO2 using electrified and modular processes that forgo the thermal- or pressure-swing regeneration steps to concentrate CO2, eliminating the need to compress, transport, or store the gas. The conventional electrochemical conversion of CO2 with aqueous electrolytes presents limited CO2 solubility and high energy requirement to achieve industrially relevant products. Additionally, aqueous systems have competitive hydrogen evolution. In the past decade, there has been significant progress toward the design of ILs and DESs, and their composites to separate CO2 from dilute streams. In parallel, but not necessarily in synergy, there have been studies focused on a few select ILs and DESs for electrochemical reduction of CO2, often diluting them with aqueous or non-aqueous solvents. The resulting electrode-electrolyte interfaces present a complex speciation for RCC. In this review, we describe how the ILs and DESs are tuned for RCC and specifically address the CO2 chemisorption and electroreduction mechanisms. Critical bulk and interfacial properties of ILs and DESs are discussed in the context of RCC, and the potential of these electrolytes are presented through a techno-economic evaluation.
  • Placeholder
    PublicationMetadata only
    Molecular engineering of a MOF with an ionic liquid sheath for direct air separation at ambient conditions
    (Elsevier Sci Ltd, 2024) Özdemir, Ray; Department of Chemical and Biological Engineering; Department of Chemical and Biological Engineering; Durak, Özce; Habib, Nitasha; Gülbalkan, Hasan Can; Aydoğdu, Ahmet Safa; Keskin, Seda; Uzun, Alper; Koç University Tüpraş Energy Center (KUTEM) / Koç Üniversitesi Tüpraş Enerji Merkezi (KÜTEM); Koç University Surface Science and Technology Center (KUYTAM) / Koç Üniversitesi Yüzey Teknolojileri Araştırmaları Merkezi (KUYTAM); Graduate School of Sciences and Engineering; College of Engineering
    Combining ionic liquids (ILs) with metal - organic frameworks (MOFs) offers broad prospects for gas separation applications. However, identifying the best IL-MOF pair for a target gas separation solely based on experimental techniques is impractical. Herein, the promising IL and MOF combination was selected among 35,672 distinct ILs and 5,629 different MOFs by fusing computational methods at different molecular scales, density functional theory, conductor -like screening model for real solvents calculations, and grand canonical Monte Carlo simulations to engineer a MOF with an IL sheath (MOFILS) for direct air separation. The new MOFILS composed of [P 6,6,6,14 ][DCA] and PCN-250(Fe) designed at the atomic level was then experimentally synthesized after finetuning the MOF to achieve high-performance air separation. An exceptionally high ideal O 2 /N 2 selectivity of 26 was reached at 1 bar and 25 degrees C, boosting the benchmark value by four -times. The results of equilibrium and dynamic gas adsorption measurements further indicated a remarkably high selectivity of 382 for the separation of O 2 /N 2 :21/79 mixture, demonstrating the broad potential of the MOFILS designed in this work for direct air separation.
  • Placeholder
    PublicationMetadata only
    Boosting CO2 separation in porphyrinic MOF-based mixed matrix membranes via central metal atom integration
    (Elsevier Sci Ltd, 2024) Prasetya, Nicholaus; Woell, Christof; Department of Chemical and Biological Engineering; Department of Chemical and Biological Engineering; Gülbalkan, Hasan Can; Keskin, Seda; Graduate School of Sciences and Engineering; College of Engineering
    As atmospheric CO2 2 levels continue to rise, contributing to the climate crisis, there is an increasing urgency to separate this gas from others and to expedite related research. Metal-Organic Frameworks (MOFs), known for their porosity and tunability, have already made significant impacts in this field, particularly to be used as part of a membrane material. This study introduces a novel method to enhance the CO2 2 separation capabilities of MOFs-based mixed matrix membranes (MMMs). Instead of taking the traditional approach by functionalizing the MOF's ligands or varying the metal or metal-oxo MOF nodes, we harness the properties of metal atoms by integrating them as central elements within porphyrinic MOF linkers through a simple post-metalation method. As a result, by incorporating the post-metalated MOF-525 as fillers into the 6FDA-DAM (6FDA: 2,2-bis(3,4dicarboxyphenyl)hexafluoropropane dianhydride;DAM: 2,4,6-trimethyl-1,3-diaminobenzene) polymer to fabricate MMMs, we effectively demonstrate improved CO2/N2 2 /N 2 and CO2 2 /CH4 4 gas separation capabilities of around 20 % without the necessity to use a very high MOF loading (only 2 wt%). Further analysis on the gas transport reveals that such a performance improvement mainly comes from the enhanced CO2 2 solubility, which might be attributed to the presence of the metal atoms in the post-metalated MOF 525. Lastly, in order to get a more comprehensive understanding, we also carry out a computational study as a tool to validate and predict the experimental results of our MMMs. This study then opens up the possibility to further investigate the efficacy of introducing various metal atoms in other porphyrinic MOFs when they are used as fillers to significantly boost the CO2 2 separation performance of MMMs.
  • Placeholder
    PublicationMetadata only
    Combining computational screening and machine learning to explore MOFs and COFs for methane purification
    (AIP Publishing, 2024) Department of Chemical and Biological Engineering; Department of Chemical and Biological Engineering; Gülbalkan, Hasan Can; Uzun, Alper; Keskin, Seda; Graduate School of Sciences and Engineering; College of Engineering
    Metal-organic frameworks (MOFs) and covalent organic frameworks (COFs) have great potential to be used as porous adsorbents and membranes to achieve high-performance methane purification. Although the continuous increase in the number and diversity of MOFs and COFs is a great opportunity for the discovery of novel adsorbents and membranes with superior performances, evaluating such a vast number of materials in the quickest and most effective manner requires the development of computational approaches. High-throughput computational screening based on molecular simulations has been extensively used to identify the most promising MOFs and COFs for methane purification. However, the enormous and ever-growing material space necessitates more efficient approaches in terms of time and effort. Combining data science with molecular simulations has recently accelerated the discovery of optimal MOF and COF materials for methane purification and revealed the hidden structure-performance relationships. In this perspective, we highlighted the recent developments in combining high-throughput molecular simulations and machine learning to accurately identify the most promising MOF and COF adsorbents and membranes among thousands of candidates for separating methane from other gases including acetylene, carbon dioxide, helium, hydrogen, and nitrogen. After providing a brief overview of the topic, we reviewed the pioneering contributions in the field and discussed the current opportunities and challenges that we need to direct our efforts for the design and discovery of adsorbent and membrane materials.
  • Placeholder
    PublicationMetadata only
    Computational simulations of metal–organic frameworks to enhance adsorption applications
    (John Wiley and Sons Inc, 2024) Department of Chemical and Biological Engineering; Department of Chemical and Biological Engineering; Harman, Hilal Dağlar; Gülbalkan, Hasan Can; Aksu, Gökhan Önder; Keskin, Seda; Graduate School of Sciences and Engineering; College of Engineering
    Metal–organic frameworks (MOFs), renowned for their exceptional porosity and crystalline structure, stand at the forefront of gas adsorption and separation applications. Shortly after their discovery through experimental synthesis, computational simulations quickly become an important method in broadening the use of MOFs by offering deep insights into their structural, functional, and performance properties. This review specifically addresses the pivotal role of molecular simulations in enlarging the molecular understanding of MOFs and enhancing their applications, particularly for gas adsorption. After reviewing the historical development and implementation of molecular simulation methods in the field of MOFs, high-throughput computational screening (HTCS) studies used to unlock the potential of MOFs in CO2 capture, CH4 storage, H2 storage, and water harvesting are visited and recent advancements in these adsorption applications are highlighted. The transformative impact of integrating artificial intelligence with HTCS on the prediction of MOFs’ performance and directing the experimental efforts on promising materials is addressed. An outlook on current opportunities and challenges in the field to accelerate the adsorption applications of MOFs is finally provided. © 2024 The Author(s). Advanced Materials published by Wiley-VCH GmbH.
  • Placeholder
    PublicationMetadata only
    Rapid and accurate screening of the COF space for natural gas purification: COFInformatics
    (American Chemical Society, 2024) Department of Chemical and Biological Engineering; Department of Chemical and Biological Engineering; Aksu, Gökhan Önder; Keskin, Seda; Graduate School of Sciences and Engineering; College of Engineering
    In this work, we introduced COFInformatics, a computational approach merging molecular simulations and machine learning (ML) algorithms, to evaluate all synthesized and hypothetical covalent organic frameworks (COFs) for the CO2/CH4 mixture separation under four different adsorption-based processes: pressure swing adsorption (PSA), vacuum swing adsorption (VSA), temperature swing adsorption (TSA), and pressure-temperature swing adsorption (PTSA). We first extracted structural, chemical, energy-based, and graph-based molecular fingerprint features of every single COF structure in the very large COF space, consisting of nearly 70,000 materials, and then performed grand canonical Monte Carlo simulations to calculate the CO2/CH4 mixture adsorption properties of 7540 COFs. These features and simulation results were used to develop ML models that accurately and rapidly predict CO2/CH4 mixture adsorption and separation properties of all 68,614 COFs. The most efficient separation process and the best adsorbent candidates among the entire COF spectrum were identified and analyzed in detail to reveal the most important molecular features that lead to high-performance adsorbents. Our results showed that (i) many hypoCOFs outperform synthesized COFs by achieving higher CO2/CH4 selectivities;(ii) the top COF adsorbents consist of narrow pores and linkers comprising aromatic, triazine, and halogen groups;and (iii) PTSA is the most efficient process to use COF adsorbents for natural gas purification. We believe that COFInformatics promises to expedite the evaluation of COF adsorbents for CO2/CH4 separation, thereby circumventing the extensive, time- and resource-intensive molecular simulations.
  • Placeholder
    PublicationMetadata only
    [BMIM][OAc] coating layer makes activated carbon almost completely selective for CO2
    (Elsevier Science Sa, 2022) N/A; N/A; Department of Chemical and Biological Engineering; Department of Chemical and Biological Engineering; Department of Chemical and Biological Engineering; Durak, Özce; Zeeshan, Muhammad; Keskin, Seda; Uzun, Alper; Master Student; PhD Student; Faculty Member; Faculty Member; Koç University Tüpraş Energy Center (KUTEM) / Koç Üniversitesi Tüpraş Enerji Merkezi (KÜTEM); Koç University Surface Science and Technology Center (KUYTAM) / Koç Üniversitesi Yüzey Teknolojileri Araştırmaları Merkezi (KUYTAM); Graduate School of Sciences and Engineering; Graduate School of Sciences and Engineering; College of Engineering; College of Engineering; N/A; N/A; 40548; 59917
    Tuning the molecular affinity of porous materials towards desired gases is important to achieve superior selectivity for a target separation. Herein, we report a novel composite, prepared by coating an ordinary activated carbon (AC) with an ionic liquid (IL) (1-butyl-3-methylimidazolium acetate, [BMIM][OAc]) offering an almost complete CO2 selectivity over N-2 and CH4. Data indicated that pore blockage by the IL accompanied with the enhancement in polarity and reduction in the hydrophobic character of the surface hindered the sorption of N-2 and CH4. For CO2, on the other hand, new chemisorption and physisorption sites became available associated with the IL layer on the surface, making the composite material significantly selective. Newly formed chemisorption sites attributed to the cation's acidic C2H sites, which become available with bi-layer formation. Presence of multiple competitive sorption sites with different energies was further proven with thermal analysis and detailed spectroscopic analysis. Data showed that CO2/CH4 and CO2/N-2 ideal selectivities boosted from 3.3 to 688.3 (2.3 to 54.7) and from 15.6 to 903.7 (7.1 to 74.3) at 0.1 (1) bar and 25 degrees C, respectively, upon the deposition of IL layer. Especially at lower pressures, the IL/AC material became almost fully selective for CO2 offering ideal selectivities in the order of several tens of thousands. To the best of our knowledge, the remarkable enhancement in the ideal CO2 selectivity by a straightforward post-synthesis modification of an ordinary AC, as reported here, sets a new benchmark in high-performance and efficient gas separation for similar porous materials.
  • Placeholder
    PublicationMetadata only
    Opportunities and challenges of MOF-based membranes in gas separations
    (Elsevier, 2015) Avci, Ahmet K.; N/A; Department of Chemical and Biological Engineering; Department of Chemical and Biological Engineering; Adatoz, Elda Beruhil; Keskin, Seda; PhD Student; Faculty Member; Graduate School of Sciences and Engineering; College of Engineering; N/A; 40548
    Gas separation using metal organic framework (MOF) membranes has become an increasingly important research field over the last years. Several recent studies have shown that thin-film MOF membranes and MOF/polymer composite membranes can outperform well known polymer and zeolite membranes in various gas separation applications. The continuously increasing number of experimental and computational studies emphasizes the superior membrane properties of MOFs. In this review, we present a summary of experimental and computational studies both for thin-film MOF membranes and MOF/polymer composite membranes. We aim to address opportunities and challenges related with use of MOF membranes for gas separations as well as give directions on the requirements for employing these membranes in practical applications. (C) 2015 Elsevier B.V. All rights reserved.