10 results on '"Kang, Dun-Yen"'
Search Results
2. Ultra-high flux loose nanofiltration membrane based on metal organic framework (CAU-10-H)/P84 co-polyimide for dye/salt fractionation from industrial waste water
- Author
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Hundessa, Netsanet Kebede, Hu, Chien-Chieh, Kang, Dun-Yen, Chou, Pai-Chien, Ajebe, Eyasu Gebrie, Lee, Kueir-Rarn, and Lai, Juin-Yih
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- 2024
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3. Highly CO2 Selective Metal–Organic Framework Membranes with Favorable Coulombic Effect.
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Chiou, Da‐Shiuan, Yu, Hyun Jung, Hung, Ting‐Hsiang, Lyu, Qiang, Chang, Chung‐Kai, Lee, Jong Suk, Lin, Li‐Chiang, and Kang, Dun‐Yen
- Subjects
METAL-organic frameworks ,MEMBRANE separation ,PERMEABILITY ,ADSORBATES ,INDUSTRIAL applications ,CARBON dioxide - Abstract
The topology and chemical functionality of metal–organic frameworks (MOFs) make them promising candidates for membrane gas separation; however, few meet the criteria for industrial applications, that is, selectivity of >30 for CO2/CH4 and CO2/N2. This paper reports on a dense CAU‐10‐H MOF membrane that is exceptionally CO2‐selective (ideal selectivity of 42 for CO2/N2 and 95 for CO2/CH4). The proposed membrane also achieves the highest CO2 permeability (approximately 500 Barrer) among existing pure MOF membranes with CO2/CH4 selectivity exceeding 30. State‐of‐the‐art atomistic simulations provide valuable insights into the outstanding separation performance of CAU‐10‐H at the molecular level. Adsorbent–adsorbate Coulombic interactions are identified as a crucial factor in the design of CO2‐selective MOF membranes. [ABSTRACT FROM AUTHOR]
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- 2021
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4. Surface Engineering Layered Metal-Organic Framework to Enhance Processability and Stability in Water.
- Author
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Li, Yung‐Lin, Chi, Heng‐Yu, Kan, Ming‐Yang, Pao, Szu‐Ying, Kang, Yu‐Hao, Chen, Jiun‐Jen, and Kang, Dun‐Yen
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METAL-organic frameworks ,WATER chemistry ,CHEMICAL stability ,CRYSTAL morphology ,LIGANDS (Chemistry) ,HYDROPHOBIC surfaces ,THERMAL stability - Abstract
Despite considerable advancements of metal-organic frameworks (MOFs), the practical implementation of MOFs is still hindered by issues of stability and processability. In this work, we sought to overcome these difficulties through surface engineering. As a proof of concept, we subjected ZIF-L with a unique layered crystal morphology to a shell-ligand exchange reaction. This resulted in the partial replacement of 2-methylimidazole by benzimidazole as the linker in the framework on the outer surface of the crystals, thereby changing the surface of the ZIF-L crystal from hydrophilic to hydrophobic. The engineered ZIF-L (hereafter referred to as Benz-ZIF-L) formed a stable dispersion in the nonpolar solvent, hexane. The suspension of Benz-ZIF-L in hexane was applied via spin coating to a porous substrate of poly(vinylidene fluoride) (PVDF), resulting in a thin film of high density. In contrast, the application of a suspension of pure ZIF-L in the same manner did not result in the formation of a thin film. Benz-ZIF-L also exceeded pure ZIF-L with regard to hydrothermal stability and acid/base resistance. [ABSTRACT FROM AUTHOR]
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- 2017
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5. Correlating framework structures and thermoelectric performance of metal–organic framework/carbon nanotube thermoelectric hybrids with n–p type inversion.
- Author
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Lin, Meng-Hao, Hsu, Cheng-Hsun, Kang, Dun-Yen, and Liu, Cheng-Liang
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[Display omitted] • Unique oxygen doping and low thermal conductivity of metal–organic framework. • Exceptional carrier n–p type inversion behavior from gas adsorption. • Improved thermoelectric performance due to the introduction of porous structures. Metal–organic frameworks (MOFs) show considerable promise as thermoelectric materials due to the inherently low thermal conductivities provided by their unique porous frameworks. Nevertheless, their applications are impeded by poor electrical conductivities and processabilities. Herein, novel n–p type carrier transport inversion MOF/carbon nanotube (CNT) thermoelectric hybrids are developed via controlled adjustment of the MOF/CNT composition. The low thermal conductivities of the MOFs provide optimized (zT) values of 0.071 and 0.025 for the n- and p-type thermoelectric hybrids, respectively. Moreover, a flexible thermoelectric generator consisting of seven p-n junction pairs in series provides a maximum open-circuit voltage of 11.2 mV and a maximum power of around 165.5 nW at a temperature difference of 20 K. This study introduces an alternative approach to creating high zT p- and n-type thermoelectric hybrids near room temperature by manipulating the composite ratio, and establishes a correlation between the framework structure and the thermoelectric performance, thereby supporting the development of MOF-based thermoelectric materials. [ABSTRACT FROM AUTHOR]
- Published
- 2024
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- View/download PDF
6. Single-file diffusion and its influence on membrane gas separation: A case study on UTSA-280.
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Hsu, Cheng-Hsun, Lin, Chia-Yi, Wang, Hsiang-Yu, Lin, Pei-Ying, Chuang, Chia-Hui, Hsiao, Li-Wei, Chiu, Cheng-chau, and Kang, Dun-Yen
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MEMBRANE separation , *MONTE Carlo method , *CARBON dioxide , *SEPARATION of gases , *DENSITY functional theory , *ACTIVATION energy - Abstract
Gas permeation in metal-organic framework-based (MOF-based) membranes is often elucidated through the solution-diffusion model, where the adsorption and diffusion of gases play equally vital roles. This study draws attention to a unique phenomenon known as single-file diffusion (SFD) occurring within MOF membranes that possess ultramicropores with dimensions comparable to the gas molecules themselves. When SFD takes place, the separation performance becomes solely reliant on the adsorption quantities on the feed side of the membrane. As a proof of concept, we fabricated a UTSA-280 membrane and subjected it to testing using gas mixtures of CO 2 /N 2 and CO 2 /CH 4. Two crucial observations substantiate the occurrence of single-file diffusion. Firstly, in the gas mixtures, the diffusion coefficients of N 2 or CH 4 were observed to align closely with that of CO 2 , despite the intrinsic diffusion coefficients of CO 2 , N 2 , and CH 4 , as determined from single-gas permeation experiments, exhibiting differences. Secondly, the CO 2 mole fractions within the adsorption phase closely mirrored those in the gas phase on the permeate side. Given the high adsorption selectivity of UTSA-280 for CO 2 , the UTSA-280 membrane delivers outstanding permeation selectivity for CO 2 /N 2 (611) and CO 2 /CH 4 (80.7). Our experimental findings are supported by mesoscale kinetic Monte Carlo simulations, which confirmed the relation between the CO 2 compositions in the adsorption phase on the feed side and in the gas phase on the permeate side. Furthermore, density functional theory calculations revealed high energy barriers associated with CO 2 surpassing its counterparts, rendering such processes unfavorable, thereby reinforcing our experimental findings regarding single-file diffusion. [Display omitted] • The UTSA-280 membrane is fabricated through interfacial growth. • The UTSA-280 membrane exhibits high CO 2 /N 2 selectivity (611) • The UTSA-280 membrane exhibits high CO 2 /CH 4 selectivity (80.7). • Single-file diffusion within the UTSA-280 membrane is investigated. • Single-file diffusion could make permeation selectivity governed by adsorption. [ABSTRACT FROM AUTHOR]
- Published
- 2024
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7. Engineering gas separation property of metal–organic framework membranes via polymer insertion.
- Author
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Hung, Han-Lun, Iizuka, Tomoya, Deng, Xuepeng, Lyu, Qiang, Hsu, Cheng-Hsun, Oe, Noriyoshi, Lin, Li-Chiang, Hosono, Nobuhiko, and Kang, Dun-Yen
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POLYMERIC membranes , *SEPARATION of gases , *METAL-organic frameworks , *GAS engineering , *NUCLEAR magnetic resonance spectroscopy , *X-ray photoelectron spectroscopy , *SMALL molecules - Abstract
[Display omitted] • Polymers are inserted in MOF membranes for pore size engineering. • After PEG impregnation, the ZnMOF membrane presents improved separation performance for H 2 /CO 2 and H 2 /CH 4. • The novel polymer-in-MOF composite possesses a higher diffusive selectivity than pristine polymers or MOFs. We report on a novel approach to engineering the gas permeation property of metal–organic framework (MOF) membranes via polymer infiltration. This method enables MOFs of a too large intrinsic aperture size (>0.7 nm) for membrane separation of small molecules. [Zn 2 (bdc) 2 ted] n , referred to as ZnMOF, is studied as a model system for the proof of concept. This MOF has a pore limiting diameter of 7.63 Å, which is notably larger than the kinetic diameters of the gases to be separated (2.89, 3.3, and 3.8 Å for H 2 , CO 2 , and CH 4 , respectively). We prepare ZnMOF membranes, followed by the insertion of polyethylene glycol (PEG) via dip coating, spin-on deposition, or drop coating. Comprehensive materials characterization is performed via a number of solid-state techniques, including nitrogen physisorption, Fourier-transform infrared spectroscopy, thermogravimetric analysis, solution-state nuclear magnetic resonance spectroscopy, X-ray photoelectron spectroscopy, and X-ray diffraction. The results suggest that the three deposition methods all enable the infiltration of PEG in the micropores of the ZnMOF membranes. The as-made ZnMOF membrane possesses low gas selectivity (5.19 for H 2 /CO 2 and 3.8 for H 2 /CH 4), owing to its large pore size. With the PEG infiltration, the ZnMOF membrane presents good selectivity of H 2 /CO 2 (26.28) and H 2 /CH 4 (17.6). Molecular simulations also suggest that the impregnation of PEG reduces the effective pore size of the ZnMOF structure and thus renders it a higher diffusion selectivity for gas mixtures as compared to the bare PEG or the pristine ZnMOF membranes. [ABSTRACT FROM AUTHOR]
- Published
- 2023
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8. Engineering CAU-10-H in the preparation of mixed matrix membranes for gas separation.
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Yu, Hyun Jung, Chiou, Da-Shiuan, Hsu, Cheng-Hsun, Tsai, Hsin-Yu, Kan, Ming-Yang, Lee, Jong Suk, and Kang, Dun-Yen
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SEPARATION of gases , *MEMBRANE separation , *CARBON dioxide , *METAL-organic frameworks , *METAL ions , *ENGINEERING - Abstract
Metal-organic frameworks (MOFs) are highly compatible with polymers and can be used to create mixed matrix membranes (MMMs) for gas separation. Herein, we engineered the particle size as well as the number of missing linkers in CAU-10-H MOFs via either applying the plasma treatment (CAU-10-H_Plasma) or varying the water/ N , N -dimethylformamide (H 2 O/DMF) co-solvent ratios (CAU-10-H_Micro and CAU-10-H_Nano). The CAU-10-H_Nano showed the largest number of missing linkers, but the lowest adsorption uptake of CO 2 and CH 4 albeit the largest BET surface area. In contrast, both CAU-10-H_Plasma and CAU-10-H_Micro exhibited relatively high adsorption uptakes of CO 2 and CH 4. In addition, all the MMMs fabricated using 6FDA-mPDA:DABA (3:2) exhibited a good interaction between Al2+ metal ions of CAU-10-H and carboxylic groups of 6FDA-mPDA:DABA (3:2). Importantly, the 6FDA-mPDA:DABA (3:2)/CAU-10-H_Plasma (75/25 w/w) MMM exhibited more attractive selectivities of CO 2 /CH 4 and H 2 /CH 4 (e.g., 68 and 184, respectively) compared to those of the other two MMMs under single-gas conditions. It also showed the highest CO 2 /CH 4 selectivity of 67 under equimolar CO 2 /CH 4 mixed-gas conditions. As CAU-10-H_Plasma possessed the lowest quantity of defective sites among the three CAU-10-H samples, our results suggest that suppressing defective sites in MOFs could be an effective approach for enhancing the CO 2 separation efficiency. [Display omitted] • Emerging MOF, CAU-10-H, is used for preparation of MMMs. • Plasma-assisted synthesis of CAU-10-H is employed for the size and defect control. • The CAU-10-H/6FDA-mPDA:DABA (3:2)-based MMM presents CO 2 /CH 4 selectivity of 67. [ABSTRACT FROM AUTHOR]
- Published
- 2022
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9. Highly-selective MOF-303 membrane for alcohol dehydration.
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Lai, Jun-Yu, Wang, Ting-Yuan, Zou, Changlong, Chen, Jiun-Jen, Lin, Li-Chiang, and Kang, Dun-Yen
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DIFFUSION barriers , *ISOPROPYL alcohol , *MEMBRANE separation , *ALCOHOL , *DEHYDRATION , *PERVAPORATION , *ETHANOL - Abstract
Metal-organic frameworks (MOFs) are an emerging class of crystalline microporous materials, which have drawn considerable attention for separation applications. While a number of successful examples of MOF-based membranes for gas separation have been reported, only a few of pure MOF membranes presented high performance in pervaporation. This work reports on the application of a highly hydrophilic MOF, MOF-303, for dehydration of ethanol as well as isopropanol (IPA) via pervaporation. Dense MOF-303 membranes are fabricated with either a sodium hydroxide or urea solution. The latter recipe renders MOF-303 crystals a low quantity of missing linker; and it also yields a membrane with fewer pinhole-type defects. The MOF-303 membrane prepared with urea presents a relatively low air permeance and much higher separation performance for of water-ethanol and water-IPA mixtures, as compared to that synthesized with sodium hydroxide. The MOF-303-urea membrane possesses high separation factors for water/ethanol (55349) and for water/IPA (3801) at 303 K. At a higher temperature of 343 K, this membrane still offers a good water/ethanol separation factor of 1874. A 7-day pervaporation operation on the MOF-303-urea membrane demonstrates that the separation performance drops gradually during the test, but it can be restored via a thermal treatment on the membrane. Molecular simulations are performed to shed light on the transport property of water, ethanol, and IPA in MOF-303. The computational results suggest that the dehydration capability of this MOF can be attributed to both of its water-selective adsorption and diffusion, particularly the latter. Specifically, a relatively high diffusion barrier to the alcohols in MOF-303 results in the high selectivity of water over ethanol or IPA. [Display omitted] • MOF-303 membrane presents water/ethanol selectivity of nearly 60,000. • The separation performance of MOF-303 membrane can be restored through thermal reactivation. • Molecular simulations elaborate key structural characteristics of MOF-303 for its high water/alcohol selectivity. [ABSTRACT FROM AUTHOR]
- Published
- 2022
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10. Pillared-bilayer metal-organic framework membranes for dehydration of isopropanol.
- Author
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Hsieh, Yi-Jui, Zou, Changlong, Chen, Jiun-Jen, Lin, Li-Chiang, and Kang, Dun-Yen
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METAL-organic frameworks , *DIFFUSION barriers , *ISOPROPYL alcohol , *MEMBRANE separation , *POLYVINYL alcohol , *PERVAPORATION , *DEHYDRATION - Abstract
Metal-organic frameworks (MOFs) possess ordered micropores with high variety in surface functionality, and are considered excellent candidates for membrane pervaporation. However, only very few successful examples of pure MOF membranes for pervaporation have been reported to date. In this work we report on an emerging pillared-bilayer MOF, Zn-aip-azpy, with a pore limiting diameter of 3.57 Å for the pervaporation of water-IPA mixture. We find that the seeding procedure is crucial to the formation of high-quality dense membrane comprising Zn-aip-azpy. The deposition of low-molecular weight PVA is also found to be an effective approach to form a protective layer on the pure Zn-aip-azpy membrane. The optimized Zn-aip-azpy membrane presents a water-to-IPA separation factor of as high as ~2000 with a mass flux of 0.043 kg-m−2-h−1. This is for the first time that the water-to-alcohol selectivity of a pure MOF membrane can exceed 1000. A correlation between air permeance of a membrane and its separation performance is developed in this work, which can be applied to diagnose the pinhole type defects in pure MOF membranes. Molecular simulations conducted herein suggest that, while the interior surface of Zn-aip-azpy is largely alcohol selective, the narrow bottleneck in its one-dimensional channel imposes a large diffusion barrier for IPA and thus renders this membrane high water-to-IPA selectivity. [Display omitted] • Membranes comprising pillared layer MOF are prepared for pervaporation. • The MOF membrane presents a high water-to-IPA separation factor (>1,000). • The selectivity of the Zn-aip-azpy membrane outperforms other existing pure MOF membranes. [ABSTRACT FROM AUTHOR]
- Published
- 2021
- Full Text
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