Research Project: COMPOSITE MEMBRANES WITH METAL ORGANIC FRAMEWORKS FOR HIGH EFFICIENCY GAS SEPARATIONS
Loading...
Contributors
Funders
ID
EC.00020
Authors
Keskin, Seda
Faculty Member
Publications
Computational screening of metal organic frameworks for mixed matrix membrane applications
(Elsevier, 2012) Keskin, Seda; Eruçar, İlknur; Department of Chemical and Biological Engineering; Yes; College of Engineering
In this study, detailed molecular simulations were used to examine the challenge of selecting metal organic frameworks (MOFs) as filler particles in high performance mixed matrix membranes (MMMs) for separation of H2 from CH4. The predictions of theoretical permeation models for gas permeability were compared with the experimental data of IRMOF-1/Matrimid, CuBTC/PSF, CuBTC/PDMS and Cu-BPY-HFS/Matrimid MMMs. The good agreement between experiments and our theoretical predictions motivated us to estimate performances of one hundred and nineteen new MOF-based MMMs, composed of seventeen different MOFs and seven different polymers. We identified several MOF-based MMMs exhibiting very high H2 selectivity and H2 permeability relative to pure polymer membranes. Finally, we discussed the ways of selecting appropriate MOFs as filler particles for a given polymer matrix which will result in MMMs with promising properties for H2 separations.
Effects of electrostatic interactions on gas adsorption and permeability of MOF membranes
(Taylor and Francis, 2014) Eruçar, İlknur; Keskin, Seda; Manz, Thomas A.; Department of Chemical and Biological Engineering; Yes; College of Engineering
We examined the effects of electrostatic interactions on gas adsorption and permeability of metal organic framework (MOF) membranes and MOF-filled mixed matrix membranes (MMMs) for CO2/CH4, CO2/N-2 and H-2/CO2 separations using molecular simulations. Adsorption isotherms and diffusion rates of CO2, CH4, N-2 and H-2 in several MOFs were computed using grand canonical Monte Carlo and equilibrium molecular dynamics simulations, respectively. Gas permeability and selectivity of pure MOF membranes and MOF-filled MMMs were then evaluated using theoretical permeation models. The accuracy of our molecular simulations was validated by comparing theoretical predictions for gas permeability and selectivity of MOF-filled MMMs with the available experimental data. We then used the same modelling approach to predict the performance of new MOF-filled MMMs in CO2/CH4, CO2/N-2 and H-2/CO2 separations. Promising MOF/polymer combinations which offer high selectivity and permeability relative to pure polymer membranes were identified. Our results showed that including electrostatic interactions between adsorbate molecules and MOF atoms is crucial for modelling pure MOF membranes but has less significance for modelling MOF-filled MMMs whenever the MOF volume fraction, 0.30. This result suggests that preliminary screening studies of MOF-filled MMMs can be carried out without assigning partial charges to MOF atoms.
Screening metal-organic framework-based mixed-matrix membranes for CO2/CH4 separations
(American Chemical Society (ACS), 2011) Keskin, Seda; Eruçar, İlknur; Department of Chemical and Biological Engineering; Yes; College of Engineering
In this study, the challenge of selecting metal–organic frameworks (MOFs) as filler particles in high-performance mixed-matrix membranes (MMMs) was examined using atomistic and continuum modeling. We tested several theoretical permeation models, including the Maxwell, modified Maxwell, Bruggeman, Lewis–Nielson, Pal, Felske, and modified Felske models, by comparing the predictions of these models with the experimental data for IRMOF-1/Matrimid and CuBTC/Matrimid MMMs. After identifying the model making the best predictions, we examined the performance of 80 new MOF-based MMMs composed of 10 different MOFs and eight different polymers for CO2/CH4 separations. Our results show that selecting the appropriate MOF as filler particles in polymers can result in MMMs with extraordinarily high CO2 selectivities and CO2 permeabilities relative to those of pure polymer membranes. The methods introduced in this study will create many opportunities for selecting MOF/polymer combinations for MMMs with useful properties for CO2 separation applications.
Molecular modeling of mof-based mixed matrix membranes
(Bentham Science Publishers, 2014) Eruçar, İlknur; Keskin, Seda; Department of Chemical and Biological Engineering; Yes; College of Engineering
Metal organic framework (MOF)-based mixed matrix membranes (MMMs) have received significant attention in the last couple of years due to their high gas permeabilities and high gas selectivities compared to pure polymeric membranes in various gas separation applications. Computational methods that can predict the gas separation performances of MOF-based MMMs are highly valuable since experimental screening of these MMMs is not practical given the very large number of combination of MOFs and polymers. In this review, molecular modeling methods and theoretical permeation models that have been used to assess the gas separation performance of MOF-based MMMs are discussed; opportunities and challenges in modeling of MOF/polymer membranes are addressed.
High CO2 selectivity of an amine-functionalized Metal organic framework in adsorption-based and membrane-based gas separations
(American Chemical Society, 2013) Eruçar, İlknur; Keskin, Seda; Department of Chemical and Biological Engineering; Yes; College of Engineering
Molecular simulations were used to assess the potential of a new amine-functionalized metal organic framework (MOF), Zn-aminotriazolato-oxalate (Zn-Atz), in adsorption-based and membrane-based gas separations. Single-component adsorption isotherms for CO2, H-2, CH4, and N-2 were computed and compared with the available experimental isotherm data. The good agreement between experiments and simulations motivated us to predict adsorption equilibria and transport rates of CH4/H-2, CO2/H-2, CO2/CH4, and CO2/N-2 mixtures in Zn-Atz. We then used this molecular-level information to evaluate adsorption selectivity, permeation selectivity, working capacity, gas permeability, and sorbent selection parameter of Zn-Atz for CH4/H-2, CO2/H-2, CO2/CH4, and CO2/N-2 separations. The separation performance of Zn-Atz was compared with several other nanoporous adsorbents and membranes. Finally, the selectivity and permeability of mixed matrix membranes where Zn-Atz was used as filler particles were evaluated by combining molecular simulations and continuum modeling. Our results showed that this amine-functionalized MOF is a very good candidate especially for separation of CO2 from other gases both in adsorption-based and membrane-based separations due to its high affinity for CO2.
