97 results on '"Woo Taik Lim"'
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2. Reverse Anti-solvent Crystallization Process for the Facile Synthesis of Zinc Tetra(4-pyridyl)porphyrin Single Crystalline Cubes
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Yohwan Park, Misun Hong, Jin Young Koo, Minkyung Lee, Jinho Lee, Dae Jun Moon, So Hyeong Sohn, Taiha Joo, Woo Taik Lim, Hyunseob Lim, and Hee Cheul Choi
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Medicine ,Science - Abstract
Abstract Synthesis of morphologically well-defined crystals of metalloporphyrin by direct crystallization based on conventional anti-solvent crystallization method without using any additives has been rarely reported. Herein, we demonstrate an unconventional and additive-free synthetic method named reverse anti-solvent crystallization method to achieve well-defined zinc-porphyrin cube crystals by reversing the order of the addition of solvents. The extended first solvation shell effect mechanism is therefore suggested to support the synthetic process by providing a novel kinetic route for reaching the local supersaturation environment depending on the order of addition of solvents, which turned out to be critical to achieve clean cube morphology of the crystal. We believe that our work not only extends fundamental knowledge about the kinetic process in binary solvent systems, but also enables great opportunities for shape-directing crystallization of various organic and organometallic compounds.
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- 2017
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- View/download PDF
3. Crystallographic study of direct methanol oxidation to formaldehyde by the fully Mn2+-exchanged zeolite Y (FAU, Si/Al = 1.56)
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Hyeon Seung Lim, Sayantika Nath, and Woo Taik Lim
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Mechanics of Materials ,Mechanical Engineering ,General Materials Science - Published
- 2022
4. Structural study of a cyclopentane sorption complex of fully dehydrated H-ZSM-5 (Si/Al = 24), |H3.8(C5H10)1.47|[Al3.8Si92.2O192]-MFI
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Hyun-Jae Lee, Bong Been Yim, Woo Taik Lim, Jong Jin Kim, Hu Sik Kim, Nam Ho Heo, and Sayantika Nath
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Materials science ,Hydrogen bond ,Mechanical Engineering ,Sorption ,Crystal ,chemistry.chemical_compound ,Crystallography ,Adsorption ,chemistry ,Mechanics of Materials ,Molecule ,General Materials Science ,Orthorhombic crystal system ,Cyclopentane ,Single crystal - Abstract
To study the cyclopentane sorption sites and the effect of sorption on the H-ZSM-5 structure, crystal of H-ZSM-5 were prepared by burning out the tetrapropylammonium cations in air. For the adsorption of cyclopentane into H-ZSM-5 crystal, the crystal was treated with zeolitically dried cyclopentane for 6 h at 297 K, and then evacuated for 600 s at this temperature and 1.1 × 10–4 Pa. The structure of a single crystal of cyclopentane sorption complex of dehydrated H-ZSM-5 (MFI, |H3.8(C5H10)1.47|[Al3.8Si92.2O192]-MFI, Si/Al = 24) has been determined crystallographically using synchrotron X-radiation in the orthorhombic space group Pnma; a = 20.141(4), b = 19.944(4), c = 13.439(3) A. It was refined using all intensities to the final error indice R1 = 0.072. The 1.47 cyclopentane molecules per unit cell are located between 5-rings in zigzag channel. The cyclopentane molecules are located perpendicular to the 10-rings of zigzag channel and parallel to the 5-rings of H-ZSM-5 framework at the center of them. Each cyclopentane molecule is held in place by 16 hydrogen bonds between all hydrogen atoms of cyclopentane and framework oxygen atoms of its 5- and 10-rings: C···O ca. 3.318 ~ 3.992 A.
- Published
- 2021
5. Crystal structure of diaqua(3,14-diethyl-2,6,13,17-tetraazatricyclo[16.4.0.07,12]docosane)copper(II) (3,14-diethyl-2,6,13,17-tetraazatricyclo[16.4.0.07,12]docosane)copper(II) tetrabromide dihydrate, [Cu(C22H44N4)(H2O)2][Cu(C22H44N4)]Br4·2H2O
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Woo Taik Lim, Jong-Ha Choi, Keon Sang Ryoo, Dohyun Moon, and Sunghwan Jeon
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biology ,Hydrogen bond ,General Chemistry ,Crystal structure ,Condensed Matter Physics ,biology.organism_classification ,Acceptor ,Solvent ,Bond length ,chemistry.chemical_compound ,Crystallography ,chemistry ,Bromide ,Tetra ,General Materials Science ,Macrocyclic ligand - Abstract
The crystal structure of the new double CuII complex salt, [Cu(L)(H2O)2][Cu(L)]Br4·2H2O (L = 3,14-diethyl-2,6,13,17-tetraazatricyclo[16.4.0.07,12]docosane, C22H44N4) has been determined using synchrotron radiation. The asymmetric unit contains one half of a [Cu(L)(H2O)2]2+ cation, one half of a [Cu(L)]2+ cation (both completed by crystallographic inversion symmetry), two bromide anions and one water solvent molecule. The CuII atom in the first complex exists in a tetragonally distorted octahedral environment with the four N atoms of the macrocyclic ligand in equatorial and two aqua ligands in axial positions, whereas the CuII atom in the second complex exists in a square-planar environment defined by the four nitrogen atoms of the macrocyclic ligand. The two macrocyclic rings adopt the most stable trans-III configuration with normal Cu—N bond lengths from 2.016 (3) to 2.055 (3) Å and an axial Cu—O bond length of 2.658 (4) Å. The crystal structure is stabilized by intermolecular hydrogen bonds involving the macrocycle N—H or C—H groups and the O—H groups of water molecules as donor groups, and the O atoms of water molecules and bromide anions as acceptor groups, giving rise to a one-dimensional network extending parallel to [100].
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- 2021
6. Facile synthesis of sub-nanometer Cd4S6+ and Cd2S2+ cluster in zeolite Y and its structural characterization
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Woo Taik Lim, Dae Jun Moon, Young Hun Kim, Hu Sik Kim, and Ho Yeon Yoo
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Materials science ,Mechanical Engineering ,Cationic polymerization ,02 engineering and technology ,010402 general chemistry ,021001 nanoscience & nanotechnology ,01 natural sciences ,Synchrotron ,0104 chemical sciences ,Ion ,law.invention ,Catalysis ,chemistry.chemical_compound ,Crystallography ,chemistry ,Mechanics of Materials ,law ,Cluster (physics) ,Sodalite ,General Materials Science ,Nanometre ,0210 nano-technology ,Zeolite - Abstract
The Cd4S6+ and Cd2S2+ clusters in the sodalite cavities were synthesized by reaction of the fully Cd2+-exchanged zeolite Y (Si/Al = 1.56) and 0.1 M Na2S(aq) solution at 294 K for 2 days. The single-crystal structure was determined at 100(1) K by synchrotron X-ray diffraction techniques in the cubic space group Fd $$\overline{3}$$ m. The structure was refined using all intensities to the final error index R1/wR2 = 0.048/0.156 (for Fo > 4σ(Fo)). Approximately 13 Cd2+ and 53 Na+ ions per unit cell were found at two and four crystallographically distinct positions, respectively: two site-Iʹ positions (in the sodalite cavities opposite double 6-rings (D6Rs)) are occupied by 5 and 7.5 Cd2+ ions, respectively, per unit cell. The 0.5 Cd2+ ions per unit cell are at site IIʹ in the sodalite cavity. The 2 Na+ ion is located at the center of the D6R (site I). The 15.5 Na+ ions per unit cell are located at site Iʹ. Site-II position is occupied by 31.5 Na+ ions per unit cell. The remaining 4 Na+ ions per unit cell are located at sites IIIʹ near triple 4-rings in the supercage. Finally, 0.5 and 1.5 S2− ions per unit cell, associated with Cd2+ ions, were found at the center of sodalite cavity and opposite 6-ring in the sodalite cavity, respectively. The 1 S2− ion at the center of the sodalite cavity is coordinated to 4 Cd2+ ions at site Iʹ to give a centered-tetrahedral cationic cluster, Cd4S6+, and the other S2− ion opposite 6-ring in the sodalite cavity bridges between two Cd2+ ions at site Iʹ to give a cationic cluster with a bent arrangement, Cd2S2+, in 6.3% and 18.8% of the sodalite cavities of zeolite Y (Si/Al = 1.56), respectively.
- Published
- 2021
7. Synthesis and single-crystal structure of sodium sulfide cationic cluster in the sodalite cavity of zeolite Y (FAU, Si/Al = 1.56)
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Dae Jun Moon and Woo Taik Lim
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Aqueous solution ,Materials science ,Mechanical Engineering ,Cationic polymerization ,02 engineering and technology ,010402 general chemistry ,021001 nanoscience & nanotechnology ,01 natural sciences ,Sodium sulfide ,0104 chemical sciences ,Ion ,Crystal ,chemistry.chemical_compound ,Crystallography ,chemistry ,Mechanics of Materials ,Sodalite ,General Materials Science ,0210 nano-technology ,Zeolite ,Single crystal - Abstract
The extraframework sodium sulfide cationic cluster, Na4S2+, has been introduced into zeolite Y (FAU, Si/Al = 1.56). A single crystal of |Na73(Na4S2+)1.0|[Si117Al75O384]-FAU was prepared by allowing aqueous 0.1 M Na2S solution to flow past a |Na75|[Si117Al75O384]-FAU crystal, and followed by vacuum dehydration at 723 K. Its structure was determined by single-crystal synchrotron X-ray diffraction techniques in the cubic space group Fd $$\overline{3}$$ m. The structure was refined using all intensities to the final error index R1/wR2 = 0.044/0.125. About 77 Na+ ions per unit cell are found at the crystallographically distinct positions, six. One Na+ ion per unit cell is at the center of double 6-ring. Two site-I′ positions are occupied by 26.5 and 4 Na+ ions, respectively, per unit cell. Thirty-two Na+ ions per unit cell are found at site II, in the supercage opposite single 6-rings. The remaining 4.5 and 9 Na+ ions per unit cell occupy two sites III′ near triple 4-rings in the supercage. Finally, one sulfide ion per unit cell, associated with Na+ ions, is found at the center of sodalite cavity. The 4 Na+ ions at site I′ coordinate to a sulfide ion at the center of sodalite cavity to give tetrahedral cationic cluster, Na4S2+. In |Na73(Na4S2+)1.0|[Si117Al75O384]-FAU, tetrahedral Na4S2+ ions center about 12.5% of the sodalite cavities.
- Published
- 2020
8. Crystal structure of di-aqua-(3,14-diethyl-2,6,13,17-tetra-aza-tri-cyclo-[16.4.0.0
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Dohyun, Moon, Sunghwan, Jeon, Woo Taik, Lim, Keon Sang, Ryoo, and Jong-Ha, Choi
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crystal structure ,synchrotron radiation ,macrocycle ,hydrogen bonding ,double copper(II) complex ,Research Communications ,bromide - Abstract
In the title complex, [Cu(C22H44N4)(H2O)2][Cu(C22H44N4)]Br4·2H2O, each of the two complex cations lies about an inversion center. The two macrocyclic rings adopt the most stable trans-III configuration. In the crystal, O—H⋯Br, N—H⋯Br, N—H⋯O and C—H⋯O hydrogen bonds connect the complex cations, bromide anions, semi-coordinating H2O ligands and water solvent molecules, forming a one-dimensional network extending parallel [100]., The crystal structure of the new double CuII complex salt, [Cu(L)(H2O)2][Cu(L)]Br4·2H2O (L = 3,14-diethyl-2,6,13,17-tetraazatricyclo[16.4.0.07,12]docosane, C22H44N4) has been determined using synchrotron radiation. The asymmetric unit contains one half of a [Cu(L)(H2O)2]2+ cation, one half of a [Cu(L)]2+ cation (both completed by crystallographic inversion symmetry), two bromide anions and one water solvent molecule. The CuII atom in the first complex exists in a tetragonally distorted octahedral environment with the four N atoms of the macrocyclic ligand in equatorial and two aqua ligands in axial positions, whereas the CuII atom in the second complex exists in a square-planar environment defined by the four nitrogen atoms of the macrocyclic ligand. The two macrocyclic rings adopt the most stable trans-III configuration with normal Cu—N bond lengths from 2.016 (3) to 2.055 (3) Å and an axial Cu—O bond length of 2.658 (4) Å. The crystal structure is stabilized by intermolecular hydrogen bonds involving the macrocycle N—H or C—H groups and the O—H groups of water molecules as donor groups, and the O atoms of water molecules and bromide anions as acceptor groups, giving rise to a one-dimensional network extending parallel to [100].
- Published
- 2021
9. A crystallographic study of Sr2+ and K+ ion-exchanged zeolite Y (FAU, Si/Al = 1.56) from binary solution with different mole ratio of Sr2+ and K+
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Man Park, Woo Taik Lim, Dae Jun Moon, Ho Yeon Yoo, Hu Sik Kim, and Jong Sam Park
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Materials science ,Ion exchange ,Mechanical Engineering ,02 engineering and technology ,Crystal structure ,010402 general chemistry ,021001 nanoscience & nanotechnology ,01 natural sciences ,0104 chemical sciences ,Catalysis ,Ion ,Crystal ,Crystallography ,Mechanics of Materials ,General Materials Science ,0210 nano-technology ,Selectivity ,Zeolite ,Bar (unit) - Abstract
To study the Sr2+-ion selectivity of zeolite Y (Si/Al = 1.56) in binary solution with different Sr2+ and K+ concentration during exchange, two single-crystals of fully dehydrated, Sr2+- and K+-exchanged zeolites Y were prepared by the flow method using a mixed ion-exchange solution whose Sr(NO3)2:KNO3 mol ratios were 1:1 (crystal 1) and 1:100 (crystal 2), respectively, with a total concentration of 0.05 M, followed by vacuum dehydration at 723 K. Their crystal structures were determined by single-crystal synchrotron X-ray diffraction techniques in the cubic space group $$ Fd\bar{3}m $$, respectively, and were refined to the final error indices R1/wR2 = 0.0429/0.1437 and 0.0356/0.1239 for crystals 1 and 2, respectively. In the structure of |Sr28K19|[Si117Al75O384]-FAU (crystal 1), 28 Sr2+ ions per unit cell occupy four different crystallographically distinct sites; 15, 2, 2, and 9 are at sites I, I′, II′, and II, respectively, whereas, the K+ ions occupy only one site: 19 are at site II. In the structure of |Sr17K41|[Si117Al75O384]-FAU (crystal 2), 17 Sr2+ ions per unit cell occupy three equipoints; 10.5, 2, and 4.5 are at sites I, I′, and II, respectively. The residual 41 K+ ions per unit cell are found at four different sites; 8, 24, 3, and 6 are at sites I′, II, III′a, and III′b, respectively. The degrees of ion exchange are 74.7 and 45.3% for crystals 1 and 2, respectively. This result shows that the degree of Sr2+ exchange decreased sharply by decreasing the initial Sr2+ concentration and increasing the initial K+ concentration in the given ion-exchange solution.
- Published
- 2019
10. Site Competition of Ca2+ and Cs+ Ions in the Framework of Zeolite Y (Si/Al = 1.56) and Their Crystallographic Studies
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Hu Sik Kim, Woo Taik Lim, and Jong Sam Park
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Crystallography ,media_common.quotation_subject ,02 engineering and technology ,010402 general chemistry ,021001 nanoscience & nanotechnology ,0210 nano-technology ,Zeolite ,01 natural sciences ,Competition (biology) ,0104 chemical sciences ,Ion ,media_common - Published
- 2018
11. Computational Design of Functional Amyloid Materials with Cesium Binding, Deposition, and Capture Properties
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Chang-Hyun Choi, Woo Taik Lim, Sai Vamshi R. Jonnalagadda, Asuka A. Orr, Hae-Kwon Jeong, Sang June Choi, Phanourios Tamamis, Anna Mitraki, Kendal J Henderson, Emmanouela Fotopoulou, and Chrysoula Kokotidou
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Protein Conformation, alpha-Helical ,0301 basic medicine ,Scaffold ,Materials science ,Cesium ,chemistry.chemical_element ,Nanotechnology ,Molecular Dynamics Simulation ,010402 general chemistry ,01 natural sciences ,03 medical and health sciences ,Molecular dynamics ,Cesium ions ,Ion binding ,Protein structure ,mental disorders ,Materials Chemistry ,Computational design ,Amino Acid Sequence ,Physical and Theoretical Chemistry ,Amyloid beta-Peptides ,Ion deposition ,Protein Structure, Tertiary ,0104 chemical sciences ,Surfaces, Coatings and Films ,030104 developmental biology ,chemistry ,Mutagenesis ,Caesium ,Protein Binding - Abstract
Amyloid materials are gaining increasing attention as promising materials for applications in numerous fields. Computational methods have been successfully implemented to investigate the structures of short amyloid-forming peptides, yet their application in the design of functional amyloid materials is still elusive. Here, we developed a computational protocol for the design of functional amyloid materials capable of binding to an ion of interest. We applied the protocol in a test case involving the design of amyloid materials with cesium ion deposition and capture properties. As part of the protocol, we used an optimization-based design model to introduce mutations at non-β-sheet residue positions of an amyloid designable scaffold. The designed amino acids introduced to the scaffold mimic how amino acids bind to cesium ions according to experimentally resolved structures and also aim at energetically stabilizing the bound conformation of the pockets. The optimum designs were computationally validated using a series of simulations and structural analysis to select the top designed peptides, which are predicted to form fibrils with cesium ion binding properties for experimental testing. Experiments verified the amyloid-forming properties of the selected top designed peptides, as well as the cesium ion deposition and capture properties by the amyloid materials formed. This study demonstrates the first, to the best of our knowledge, computational design protocol to functionalize amyloid materials for ion binding properties and suggests that its further advancement can lead to novel, highly promising functional amyloid materials of the future.
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- 2018
12. Facile synthesis of Cd-substituted zeolitic-imidazolate framework Cd-ZIF-8 and mixed-metal CdZn-ZIF-8
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Víctor Varela-Guerrero, Woo Taik Lim, Hae-Kwon Jeong, Liya Semenchenko, Jingze Sun, and Maria Fernanda Ballesteros Rivas
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Materials science ,Organic base ,02 engineering and technology ,General Chemistry ,010402 general chemistry ,021001 nanoscience & nanotechnology ,Condensed Matter Physics ,Molecular sieve ,01 natural sciences ,0104 chemical sciences ,chemistry.chemical_compound ,chemistry ,Chemical engineering ,Mechanics of Materials ,Propane ,Molecule ,General Materials Science ,Methanol ,Gas separation ,0210 nano-technology ,Triethylamine ,Zeolitic imidazolate framework - Abstract
Zeolitic-imidazole framework ZIF-8 has attracted tremendous interests for the high-resolution kinetic separation of propylene/propane mixture due to its effective aperture size in between the sizes of propylene and propane molecules. It is of great interest to fine-tune the effective aperture size of ZIF-8 either to improve its propylene/propane separation performances or to extend its use to the separation of other gas mixtures. It has been shown that substituting Zn with other metal nodes (e.g. Co) is a potential means to fine-tune the effective aperture size of ZIF-8. Here, we attempt to introduce another metal center, Cd, into ZIF-8 in a facile and scalable manner. Phase-pure Cd-ZIF-8 was successfully synthesized in methanol using a conventional solvothermal method, although it showed a narrow synthesis window. The presence of an organic base (triethylamine, TEA) was found critical not only for the facile synthesis of phase-pure Cd-ZIF-8 but also for the suppression of its phase transformation. A battery of characterizations including single-crystal X-ray structure solutions confirmed that the effective aperture size of Cd-ZIF-8 is the largest among its iso-structures (Zn-ZIF-8 and Co-ZIF-8). Finally, for the first time, mixed-metal CdZn-ZIF-8 crystals with various Cd/Zn ratios were solvothermally synthesized, demonstrating a further opportunity for varying the effective aperture sizes of ZIF-8 and its iso-structures.
- Published
- 2018
13. Crystallographic study on the selectivity, occupancy, and distribution of Sr2+ ions within zeolite Y in the presence of competing Na+ ions in aqueous exchange solution
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Dae Jun Moon, Hu Sik Kim, and Woo Taik Lim
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Materials science ,Aqueous solution ,Molar concentration ,Ion exchange ,Mechanical Engineering ,02 engineering and technology ,010402 general chemistry ,021001 nanoscience & nanotechnology ,01 natural sciences ,0104 chemical sciences ,Ion ,Crystal ,Crystallography ,Mechanics of Materials ,General Materials Science ,0210 nano-technology ,Selectivity ,Zeolite ,Bar (unit) - Abstract
Three single-crystals of fully dehydrated and partially Sr2+-exchanged zeolites Y (Si/Al = 1.56) were prepared by the flow method using mixed ion-exchange solutions. The Sr(NO3)2:NaNO3 molar ratios of the ion exchange solution were 1:100 (crystal 1), 1:250 (crystal 2), and 1:500 (crystal 3) with a total concentration of 0.05 M. The single-crystals were then vacuum dehydrated at 723 K and 1 × 10−4 Pa for 2 days. The structures of the crystals were determined by single-crystal synchrotron X-ray diffraction technique in the cubic space group $$Fd\bar {3}m$$ , at 100(1) K, and were then refined to the final error indices of R1/wR2 = 0.044/0.167, 0.051/0.175, and 0.069/0.219 for crystals 1, 2, and 3, respectively. The unit-cell formulas of crystals 1, 2, and 3 were |Sr17Na41|[Si117Al75O384]-FAU, |Sr13Na49|[Si117Al75O384]-FAU, and |Sr9Na57|[Si117Al75O384]-FAU, respectively. In all three crystals, the Sr2+ ions preferred to occupy site I in the D6Rs, with the remainder occupying site II. The Sr2+ ions are also located at site I′ in crystal 1. On the other hand, the Na+ ions are located at sites I′, II, and III′ in all crystals. With increasing the molar concentration of Na+ in the given exchange solution, the occupancies of the Sr2+ ions at sites I, I′, and II decreased, whereas the occupancies of the Na+ ions at sites I′, II, and III′ increased.
- Published
- 2018
14. Crystallographic studies of fully dehydrated partially Zn2+-exchanged zeolite Y (FAU, Si/Al = 1.56) depending on Zn2+ concentration of aqueous solution during exchange
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Woo Taik Lim, Sang June Choi, and Dae Jun Moon
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Diffraction ,Materials science ,Aqueous solution ,Mechanical Engineering ,02 engineering and technology ,Crystal structure ,010402 general chemistry ,021001 nanoscience & nanotechnology ,medicine.disease ,01 natural sciences ,0104 chemical sciences ,Catalysis ,Crystal ,Crystallography ,Mechanics of Materials ,medicine ,General Materials Science ,Dehydration ,0210 nano-technology ,Zeolite ,Bar (unit) - Abstract
Four single crystals of fully dehydrated and partially Zn2+-exchanged zeolites Y (Si/Al = 1.56) were prepared by the static ion-exchange method using a mixed ion-exchange solution in which Zn(NO3)2:NaCl mole ratios were 1:1 (crystal 1), 1:25 (crystal 2), 1:50 (crystal 3), and 1:100 (crystal 4), respectively, with a total concentration of 0.05 M, and followed by vacuum dehydration at 673 K. Their single-crystal structures were determined by single-crystal synchrotron X-ray diffraction techniques in the cubic space group Fd $$\bar {3}$$ m and refined to the final error indices R1/wR2 = 0.0459/0.1454, 0.0449/0.1283, 0.0427/0.1284, and 0.0486/0.1680, respectively. Their unit-cell formulas are |Zn25Na25|[Si117Al75O384]-FAU (crystal 1), |Zn19.5Na36|[Si117Al75O384]-FAU (crystal 2), |Zn19.5Na36|[Si117Al75O384]-FAU (crystal 3), and |Zn7Na61|[Si117Al75O384]-FAU (crystal 4), respectively. The degree of Zn2+ exchange decreases from 67 to 19% as the initial concentration of Zn2+ decrease and the initial concentration of Na+ increases in given ion-exchange solutions.
- Published
- 2018
15. Reaction of fully indium-exchanged zeolite A with hydrogen sulfide. Crystal structures of indium-exchanged zeolite A containing In (sub)2 S, InSH, sorbed H (sub)2 S, and (In (sub)5) (super)7+
- Author
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Nam Ho Heo, Chang Woo Chun, Jong Sam Park, Woo Taik Lim, Man Park, Song-Lin Li, and Ling-Ping Zhou
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Chemistry, Physical and theoretical -- Research ,Zeolites -- Physiological aspects ,Indium -- Physiological aspects ,Hydrogen sulfide -- Physiological aspects ,Crystals -- Physiological aspects ,Chemicals, plastics and rubber industries - Published
- 2002
16. Synthesis and Structural Characterization of Benzene-sorbed Cd2+-Y(FAU) Zeolite
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Jong Sam Park, Jeong-Min Suh, Woo Taik Lim, Sik Young Choi, and Dae Jun Moon
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chemistry.chemical_compound ,Chemistry ,Benzene ,Zeolite ,Nuclear chemistry ,Characterization (materials science) - Published
- 2017
17. Crystallographic studies on the site selectivity of Ca2+, K+, and Rb+ ions within zeolite Y (Si/Al = 1.56)
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Woo Taik Lim, Hu Sik Kim, and Young Hun Kim
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Mechanical Engineering ,Potassium ,Site selectivity ,chemistry.chemical_element ,02 engineering and technology ,010402 general chemistry ,021001 nanoscience & nanotechnology ,01 natural sciences ,0104 chemical sciences ,Ion ,Rubidium ,Catalysis ,Crystal ,Crystallography ,chemistry ,Mechanics of Materials ,Torr ,General Materials Science ,0210 nano-technology ,Zeolite - Abstract
The single-crystals of Ca2+, K+-exchanged zeolite Y, and Ca2+, Rb+-exchanged zeolite Y were prepared by using flow method with mixed ion-exchange solution, whose Ca(NO3)2:KNO3 mole ratios were 1:1 (crystal 1) and 1:100 (crystal 2), and Ca(NO3)2:RbNO3 mole ratios were 1:1 (crystal 3) and 1:100 (crystal 4), respectively, with a total concentration of 0.05 M. They were fully dehydrated by vacuum dehydration at 723 K and 1 × 10−6 Torr for 2 days. Their crystals were determined by single-crystal synchrotron X-ray diffraction techniques in the cubic space group $$Fd \overline{3}$$ m, respectively, and were refined to the final error indices R 1/wR 2 = 0.057/0.196, 0.073/0.223, 0.055/0.188, and 0.049/0.175 for crystals 1, 2, 3, and 4, respectively. In the structure of crystal 1 (|Ca23K29|[Si117Al75O384]-FAU), 23 Ca2+ ions per unit cell occupy sites I, II′, and II; 29 K+ ions per unit cell are at sites II′, II, and III′. In the structure of crystal 2 (|Ca18.5K38|[Si117Al75O384]-FAU), 18.5 Ca2+ ions per unit cell occupy sites I, I′, and II; 38 K+ ions are at sites I′, II, and III′. In the structure of crystal 3 (|Ca27Rb21|[Si117Al75O384]-FAU), 27 Ca2+ ions per unit cell occupy sites I, II′, and II; 21 Rb+ ions per unit cell are at sites II′, II, and III. In the structure of crystal 4 (|Ca18Rb39|[Si117Al75O384]-FAU), 18 Ca2+ ions per unit cell occupy sites I and II; 39 Rb+ ions per unit cell are at sites I′, II′, II, III, and III′. In the four crystals, the Ca2+ ion which has much smaller size and higher charge than other cations such as K+ and Rb+ energetically preferred at site I and so the first to be filled on it. Unlike Ca2+ ion, no K+ and Rb+ ions are found at site I, which are clearly less favorable for K+ and Rb+ ions.
- Published
- 2016
18. Minireview of pentatomic cations in sodalite cavities
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Dae Jun Moon and Woo Taik Lim
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Mineral ,Mechanical Engineering ,Cationic polymerization ,02 engineering and technology ,010402 general chemistry ,021001 nanoscience & nanotechnology ,01 natural sciences ,0104 chemical sciences ,Catalysis ,chemistry.chemical_compound ,Crystallography ,chemistry ,Mechanics of Materials ,Sodalite ,General Materials Science ,0210 nano-technology - Abstract
Centered-tetrahedral cationic clusters are frequently found in the sodalite cavities of zeolites and in the cavities of analogues of the mineral sodalite. Examples are Mn4S6+, Fe4Te6+, Zn4Se6+, Cd4S6+, Cu4Cl7+, Na4Cl3+, Na4I3+, Na54+, In57+, Ga57+, and Sn512+.
- Published
- 2019
19. Crystal structure of diaqua(3,14-diethyl-2,6,13,17-tetraazatricyclo[16.4.0.07,12]docosane)copper(II) (3,14-diethyl-2,6,13,17-tetraazatricyclo[16.4.0.07,12]docosane)copper(II) tetrabromide dihydrate, [Cu(C22H44N4)(H2O)2][Cu(C22H44N4)]Br4·2H2O.
- Author
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Dohyun Moon, Sunghwan Jeon, Woo Taik Lim, Keon Sang Ryoo, and Jong-Ha Choi
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CRYSTAL structure ,MACROCYCLIC compounds ,SYNCHROTRON radiation ,CHEMICAL bond lengths ,COPPER ,HYDROGEN bonding ,ATOMS ,SCHIFF bases - Abstract
The crystal structure of the new double Cu
II complex salt, [Cu(L)(H2 O)2 ][Cu(L)]Br4 ·2H2 O (L = 3,14-diethyl-2,6,13,17-tetraazatricyclo[16.4.0.07,12 ]docosane, C22 H44 N4 ) has been determined using synchrotron radiation. The asymmetric unit contains one half of a [Cu(L)(H2 O)2 ]2+ cation, one half of a [Cu(L)]2+ cation (both completed by crystallographic inversion symmetry), two bromide anions and one water solvent molecule. The CuII atom in the first complex exists in a tetragonally distorted octahedral environment with the four N atoms of the macrocyclic ligand in equatorial and two aqua ligands in axial positions, whereas the CuII atom in the second complex exists in a square-planar environment defined by the four nitrogen atoms of the macrocyclic ligand. The two macrocyclic rings adopt the most stable trans-III configuration with normal Cu—N bond lengths from 2.016 (3) to 2.055 (3) Å and an axial Cu—O bond length of 2.658 (4) Å. The crystal structure is stabilized by intermolecular hydrogen bonds involving the macrocycle N—H or C—H groups and the O—H groups of water molecules as donor groups, and the O atoms of water molecules and bromide anions as acceptor groups, giving rise to a one-dimensional network extending parallel to [100]. [ABSTRACT FROM AUTHOR]- Published
- 2021
- Full Text
- View/download PDF
20. Behavior of cesium cation in zeolite Y (FAU, Si/Al = 1.56) and their single-crystal structures, |Cs75−xNax|[Si117Al75O384]-FAU (x = 35 and 54)
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Hu Sik Kim, Woo Taik Lim, and Sang June Choi
- Subjects
Aqueous solution ,Ion exchange ,010405 organic chemistry ,Chemistry ,Mechanical Engineering ,Inorganic chemistry ,chemistry.chemical_element ,010402 general chemistry ,01 natural sciences ,0104 chemical sciences ,Ion ,Catalysis ,Crystal ,Crystallography ,Mechanics of Materials ,Caesium ,General Materials Science ,Zeolite ,Single crystal - Abstract
To study the tendency of Cs+ exchange into zeolite Y (Si/Al = 1.56) dependence on Cs+ and Na+ concentration of aqueous solution during exchange, two single-crystals of fully dehydrated, Cs+-and Na+-exchanged zeolites Y were prepared by the flow method using a mixed ion-exchange solution whose CsNO3:NaNO3 mol ratios were 1:1 (crystal 1) and 1:100 (crystal 2), respectively, with a total concentration of 0.1 M, followed by vacuum dehydration at 723 K. Their crystals were determined by single-crystal synchrotron X-ray diffraction techniques in the cubic space group Fd $$\overline{ 3}$$ m, respectively, and were refined to the final error indices R 1/wR 2 = 0.084/0.248 and 0.088/0.274 for crystals 1 and 2, respectively. In the structure of |Cs40Na35|[Si117Al75O384]-FAU (crystal 1), 40 Cs+ ions per unit cell occupy five different equipoints; 3, 3, 14, 9, and 11 are at sites I, II′, II, IIIa and IIIb, respectively, whereas, the remaining 35 Na+ ions occupy three different sites: 9, 11, and 15 are at sites I, I′, and II, respectively. In the structure of |Cs21Na54|[Si117Al75O384]-FAU (crystal 2), 21 Cs + ions per unit cell occupy three equipoints; 4, 6, and 11 are at sites II, IIIa, and IIIb, respectively. The residual 54 Na+ ions per unit cell are found at three different sites; 6, 20 and 28 are at sites I, I′, and II, respectively. The degrees of ion exchange are 53 and 28 % for crystals 1and 2, respectively. This result shows that the degree of Cs+ exchange decreased sharply by decreasing the initial Cs+ concentration and increasing the initial Na+ concentration in given ion-exchange solution.
- Published
- 2016
21. Characterization of Natural Zeolite and Study of Adsorption Properties of Heavy Metal Ions for Development of Zeolite Mine
- Author
-
Young Hun Kim, Hu Sik Kim, Kitae Baek, and Woo Taik Lim
- Subjects
Albite ,Adsorption ,Chemistry ,Metal ions in aqueous solution ,Inorganic chemistry ,Cation-exchange capacity ,Zeolite ,Characterization (materials science) ,Ion - Abstract
The six natural zeolites collected in Pohang area, Kyungsangbuk-do, Korea, were characterized by XRD, XRF, DTA, TGA, and CEC analysis. The primary species of these zeolite are modenite, albite, and quarts in Kuryongpo-A (Ku-A), Kuryongpo-B (Ku-B), Kuryongpo-C (Ku-C), Donghae-A (Dh-A), Donghae-B (Dh-B), and Donghae-C (Dh-C) samples. The XRF analysis showed that the six zeolites contain Si, Al, Na, K, Mg, Ca, and Fe. Cation exchange capacity of Kuryongpo-C (Ku-C) zeolite was the highest compared to other zeolites. The capabilities of removing heavy metal ions such as , and were compared. The effect of reaction time in removing heavy metal ions was studied. The experimental results showed that the efficiency of removal was low for , and ions. These may be caused by the low content of zeolite in the six natural zeolites. This indicates that the adsorption capacity roughly tends to depend on the zeoite contents, ie., the grade of zeolite ore.
- Published
- 2015
22. Synthesis of nanoporous materials to dispense pheromone for trapping agricultural pests
- Author
-
Woo Taik Lim, Ha Young Lee, Sung Man Seo, Sang June Choi, Jihyun An, and Jae Myeong Lee
- Subjects
0106 biological sciences ,Chemistry ,Nanoporous ,Mechanical Engineering ,Riptortus pedestris ,Cationic polymerization ,02 engineering and technology ,Trapping ,Microporous material ,021001 nanoscience & nanotechnology ,01 natural sciences ,010602 entomology ,Chemical engineering ,Pulmonary surfactant ,Mechanics of Materials ,Pheromone ,General Materials Science ,0210 nano-technology ,Zeolite - Abstract
In this study, to develop an effective pheromone dispenser, zeolite A was modified with cetyltrimethylammonium ion as a cationic surfactant. Its capacity for aggregation of the pheromone components was confirmed by total organic carbon analysis before and after field testing. Furthermore, weekly examinations of soybean fields (Daewonkong variety) and plum orchards were undertaken from April to August in 2014 to determine the number of Riptortus pedestris trapped by the aggregation pheromone dispersed from the pheromone loaded surfactant-modified zeolite A (SMZ-A) in a netted cylindrical trap. The powder-type SMZ-A exhibited superior performance when compared to other dispensers in a comparative study of attractiveness using cylinder- and powder-type surfactant-modified zeolite A (CSMZ-A and PSMZ-A), microporous titanosilicate ETS-10, and a commercial product (CP). The performance followed the trend PSMZ-A > > CSMZ-A > ETS-10 > CP, suggesting that the SMZ-A material has potential as a slow-releasing pheromone dispenser.
- Published
- 2015
23. Structural comparison of partially dehydrated partially Co2+-exchanged zeolites X (FAU, Si/Al = 1.40) and Y (FAU, Si/Al = 1.70)
- Author
-
Sung Man Seo, Seong Oon Ko, and Woo Taik Lim
- Subjects
Ion exchange ,Chemistry ,Mechanical Engineering ,chemistry.chemical_element ,02 engineering and technology ,010402 general chemistry ,021001 nanoscience & nanotechnology ,01 natural sciences ,0104 chemical sciences ,Ion ,Catalysis ,Crystallography ,Mechanics of Materials ,General Materials Science ,0210 nano-technology ,Zeolite ,Cobalt - Abstract
The structures of partially dehydrated and partially Co2+-exchanged zeolites X (Si/Al = 1.40) and Y (Si/Al = 1.70) were determined by single-crystal synchrotron X-ray diffraction techniques in the cubic space group Fd $$\overline{3}$$ m and were refined to the final error indices R 1/wR 2 = 0.0773/0.2152 and 0.0683/0.2184, respectively. Their unit-cell formulas are |Co26.1Na21(H3O)7.1(H2O)14.2|[Si112Al80O384]-FAU (a = 24.7892(2) A) and |Co29.3Na6.2(H3O)5.9(H2O)5.9|[Si121Al71O384]-FAU (a = 24.7346(2) A), respectively. In the structure of Co2+-X, Co2+ ions occupy sites I′, II′, II, and III′; the Na+ ions are at sites I′ and II. In the structure of Co2+-Y, Co2+ ions occupy sites I′, II′, II, and III′; the Na+ ions are at site I′. Because of the low pH of the Co2+ exchange solution, some H3O+ ions are observed in both structures. The number of Co2+ ions in zeolite was increased slightly as Si/Al ratio increased, and Na+ content and the unit cell constant of the framework were decreased.
- Published
- 2015
24. Characterization of Li+-ion Exchanged Zeolite Y using Organic Solvents
- Author
-
Hu Sik Kim, Woo Taik Lim, Yong Hyun Park, Jun Woo Park, Sik Young Choi, Seok Hee Lee, Ji Hyun Hwang, Jong Sam Park, and Kyun Hye Park
- Subjects
Solvent ,Crystal ,Formamide ,chemistry.chemical_compound ,Ion exchange ,Chemistry ,Inorganic chemistry ,chemistry.chemical_element ,Lithium ,Methanol ,Zeolite ,Ion - Abstract
To investigate the tendency of Li + exchange from polar organic solvents, Li + -ion exchange into zeolite Y (Si/Al = 1.56) was attempted by undried methanol (crystal 1) and formamide (crystal 2) solvent. Two single crystals of Na-Y were treated with 0.1 M LiNO3 in each of the two solvents at 323 K, followed by vacuum dehydration at 723 K. Their structures were determined by single-crystal synchrotron X-ray diffraction techniques in the cubic space group Fd3m, at 100(1) K. In both structures, Li + for Na + ions filled preferentially sites I’ and II. The remaining Na+ ions occupied sites I’, II, and III’ in both structures, in additional to above sites, and Na + ions occupied site I in crystal 2. While the 68 % exchange of Li + for Na + was achieved from undried methanol, only 40 % exchange was observed from undried formamide, indicating that the undried methanol was more effective than undried formamide as solvent for Li + exchange under the conditions employed.
- Published
- 2015
25. Synthesis and characterization of a new anionic zinc-adeninate metal–organic framework, [Zn3(ad)(BTC)2·(Me2NH2), 5.75 DMF, 0.25 H2O]
- Author
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Myung-Gil Kim, Woo Taik Lim, Sik Young Choi, Jihyun An, and Steven J. Geib
- Subjects
chemistry.chemical_classification ,Chemistry ,Mechanical Engineering ,Inorganic chemistry ,chemistry.chemical_element ,Zinc ,Tricarboxylic acid ,Tricarboxylate ,Catalysis ,Mechanics of Materials ,General Materials Science ,Metal-organic framework ,Thermal stability ,Chemical stability ,Nuclear chemistry ,Monoclinic crystal system - Abstract
A new anionic zinc-adeninate metal–organic framework, [Zn3(ad)(BTC)2·(Me2NH2), 5.75DMF, 0.25H2O] (ad = adeninate; BTC = benzene tricarboxylate; DMF = dimethylformamide), was synthesized via solvothermal reaction at 403 K for 24 h between adenine, zinc acetate dehydrate, and benzene tricarboxylic acid in DMF. The single-crystal structure of the framework was determined by single-crystal X-ray diffraction techniques in the monoclinic space group P2(1)/n and was refined to the final error indices R 1/wR 2 = 0.0663/0.1714 for I > 2sigma(I). The coordination of adenine and BTC expands the structure in different directions, resulting in a three dimensional structure. This framework contains a pore with the size ca. 6.6 × 3.9 A. The chemical stability, thermal stability, and cation-exchange characteristics were investigated by powder XRD, TGA, EDX, 1H NMR, and EA.
- Published
- 2015
26. Single-crystal structures of Zn2+-exchanged zeolite A: dependence on Zn2+ concentration of aqueous solution during exchange
- Author
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Hu Sik Kim, Sang June Choi, Ha Young Lee, Young Hun Kim, and Woo Taik Lim
- Subjects
Aqueous solution ,Ion exchange ,Mechanical Engineering ,Analytical chemistry ,Crystal structure ,Crystal ,chemistry.chemical_compound ,Crystallography ,chemistry ,Mechanics of Materials ,Sodalite ,General Materials Science ,Qualitative inorganic analysis ,Zeolite ,Single crystal - Abstract
To study the tendency of Zn2+ exchange into zeolite A, two single-crystals of fully dehydrated Zn2+-and Na+-exchanged zeolite A were prepared by the static ion-exchange method using a mixed ion-exchange solution whose Zn(NO3)2:NaNO3 mol ratios were 1:4 (crystal 1) and 3:2 (crystal 2), respectively, with a total concentration of 0.05 M, followed by vacuum dehydration at 623 K. Their single-crystal structures and chemical compositions were determined by single-crystal synchrotron X-ray diffraction techniques and electron probe microanalysis. Their structures were refined to the final error indices R 1/wR 2 = 0.0678/0.2154 and 0.0619/0.1938 for crystals 1 and 2, respectively. In both structures, the 4 Zn2+ ions are located in sodalite unit, whereas, the remaining 4 Na+ ions are located in large cavity. Unit-cell formula of two single-crystal structures is approximately |Zn4Na4|[Si12Al12O48]-LTA. This work shows that the degree of Zn2+ exchange by increasing the initial Zn2+ concentration and decreasing the initial Na+ concentration in given ion-exchange solution does not differ significantly.
- Published
- 2015
27. Estimation in a Model for Determining the Amount of Carbon in Soil and Measurement of the Influences of the Specific Factors
- Author
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Beung-Gu Son, Woon-Won Kim, Jae-Hwan Cho, Woo Taik Lim, Chang-Oh Hong, Jeong-Min Suh, Kyung-Ho Jin, Jum-Soon Kang, and Jeong-Ho Park
- Subjects
Total organic carbon ,chemistry.chemical_compound ,chemistry ,Greenhouse gas ,Climate change scenario ,Soil water ,Carbon dioxide ,Environmental engineering ,Environmental science ,Climate change ,Soil carbon ,Humus - Abstract
This study has been carried out to present the valuation system of soil carbon sequestration potentials of soil in accordance with the new climate change scenarios(RCP). For th at, by analyzing variation of soil carbon of the each type of agricultural land use, it aims to develop technology to increase the amount of carbon emissions and sequestration. Among the factors which affects the estimation of determining the soil carbon model and influence power after the measurement on soil organic carbon, under the center of a causal relationship between the explanatory variables this study were investigated. Chemical fertilizers (NPK) decrea sed with increasing the amount of soil organic carbon and as with the first experimental results, when cultivating rice than pepper, the fact that soil organic carbon content increased has been found out. The higher the carbon dioxide concentration, the higher the amount of organic carbon in the soil and this result is reliable under a 10% significance level. On the other hand, soil organic carbon, humus carbon and hot water extractable carbon has been found out that was not affected the soils depth, sames as the result of the first year. The higher concentration of carbon dioxide, the higher carbon content of humus and hot water extractable carbon content. According to IPCC 2006 Guidelines and the new climate change scenario RCP 4.5 and the measurement results of the
- Published
- 2014
28. Reverse Anti-solvent Crystallization Process for the Facile Synthesis ofZinc Tetra(4-pyridyl) porphyrin Single Crystalline Cubes
- Author
-
Minkyung Lee, Yohwan Park, Jin Young Koo, Hee Cheul Choi, Jinho Lee, Dae Jun Moon, Taiha Joo, So Hyeong Sohn, Misun Hong, Woo Taik Lim, and Hyunseob Lim
- Subjects
Materials science ,Science ,02 engineering and technology ,010402 general chemistry ,01 natural sciences ,Article ,law.invention ,Crystal ,chemistry.chemical_compound ,law ,Crystallization ,Group 2 organometallic chemistry ,Supersaturation ,Multidisciplinary ,021001 nanoscience & nanotechnology ,Porphyrin ,0104 chemical sciences ,Solvation shell ,chemistry ,Nanocrystal ,Chemical engineering ,Scientific method ,Medicine ,0210 nano-technology - Abstract
Synthesis of morphologically well-defined crystals of metalloporphyrin by direct crystallization based on conventional anti-solvent crystallization method without using any additives has been rarely reported. Herein, we demonstrate an unconventional and additive-free synthetic method named reverse anti-solvent crystallization method to achieve well-defined zinc-porphyrin cube crystals by reversing the order of the addition of solvents. The extended first solvation shell effect mechanism is therefore suggested to support the synthetic process by providing a novel kinetic route for reaching the local supersaturation environment depending on the order of addition of solvents, which turned out to be critical to achieve clean cube morphology of the crystal. We believe that our work not only extends fundamental knowledge about the kinetic process in binary solvent systems, but also enables great opportunities for shape-directing crystallization of various organic and organometallic compounds.
- Published
- 2017
29. Synthesis and Characterization of Selenium-sorbed Ca2+-exchanged Zeolite A for High-performance Feed
- Author
-
Ha Young Lee, Sung Man Seo, Hu Sik Kim, Sang Gull Lee, and Woo Taik Lim
- Subjects
Reaction temperature ,Waste management ,Chemistry ,business.industry ,chemistry.chemical_element ,Calcium ,Poultry farming ,Zeolite ,business ,Selenium ,Nuclear chemistry - Abstract
This study was carried out to develop high-performance feed using selenium-sorbed Ca 2+ -exchanged zeolite A. The contents of Se increased with increasing reaction temperature and the content of Ca 2+ ions in Ca 2+ -exchanged zeolite A. A synthesized high-performance feed (0.306 ppm) was applied to poultry farming for 4 and 7 weeks, respectively. Se contents in chicken meats and eggs were 18.8, 27.2, and 94.1 ppb and 73.7, 14.9, and 64.5 ppb for control (retail chicken meats), 4, and 7 weeks, respectively; Ca contents were 3.8, 9.9, and 11.9 ppm and 48.6, 48.3, and 53.6 ppm, respectively. In conclusion, Se and Ca contents in chicken meats increased as feeding periods increased, but significant differences were not observed in the eggs.
- Published
- 2014
30. The dependence of Co2+-exchange into zeolite FAU on its Si/Al ratio
- Author
-
Woo Taik Lim, Sung Man Seo, Karl Seff, and Nam Ho Heo
- Subjects
Aqueous solution ,Ion exchange ,Mechanical Engineering ,Inorganic chemistry ,chemistry.chemical_element ,Crystal structure ,Catalysis ,Ion ,Crystal ,Crystallography ,chemistry ,Mechanics of Materials ,General Materials Science ,Zeolite ,Cobalt - Abstract
Three single crystals of fully dehydrated, largely Co2+-exchanged zeolites X and Y were prepared by the exchange of Na80-X (|Na80|[Si112Al80O384]-FAU, Si/Al = 1.40), Na75-Y (|Na75|[Si117Al75O384]-FAU, Si/Al = 1.56), and Na71-Y (|Na71|[Si121Al71O384]-FAU, Si/Al = 1.70) with aqueous streams 0.05 M in Co(NO3)2, pH = 5.1, at 294 K for 3 days. This was followed by vacuum dehydration at 673 K. Their crystal structures were determined by synchrotron X-ray diffraction techniques in the cubic space group Fd $$\overline{3}$$ m at 100(1) K. In all three crystals Co2+ ions occupy the 6-ring sites I, I’, and II; Na+ ions occupy sites II’ and II. The number of Co2+ ions exchanging into the zeolite was about 30 per unit cell for all three crystals. The number of residual Na+ ions, however, decreased sharply as Si/Al ratio increased, and the number of H+ ions co-exchanging into the zeolite decreased nearly to zero. Some dealumination of the zeolite framework was seen in the first crystal (initial Si/Al = 1.40).
- Published
- 2014
31. Effect of Seeds Treatment on Germinablity of Tetragonia Tetragonides Seeds
- Author
-
Young-Hoon Park, Beung-Gu Son, Woo Taik Lim, Jeong-Min Suh, So Hee Kim, Jum-Soon Kang, Eun-Ji Park, You Heo, and Young-Whan Choi
- Subjects
chemistry.chemical_compound ,Tetragonia ,Plant growth ,Human fertilization ,Stratification (seeds) ,chemistry ,Agronomy ,Germination ,Seed treatment ,Seed dormancy ,food and beverages ,Priming (agriculture) ,Biology - Abstract
Tetragonia tetragonides is a medicinal plant native to ocean sand soil of southern provinces and has significant effects on the prevention and curing of gastroenteric disorders. Despite of its popularity, supply of the plant has never met the level of demand because of the absence of an adequate culturing method. The present study, thereby, was conducted for classifying the plants with geographically different characteristics, studying growth habits, developing a new culturing method and establishing a large scale propagation system of selected superior individual plants. The study was also aimed for revealing optimum conditions for seed treatment, fertilization, and efficient culturing system and thereby, for utilizing the plant as a new income source for rural communities. The seed was elongated with size of 2.6 mm (width) 1.8 mm (length). No difference in seed size was observed depending on different inhabitate. Each flower produced about 4.5~4.8 seeds. Germination rate was high for seeds matured for 40 days after fertilization, but deceased to 50% for seeds matured only for 20 or 30 days. Seed dormancy lasted 6 months and seed storage at humid facilitated germination. Mechanical obstruct of seed germination was due to seed coat and removal of seed coat enhanced the germination rate. Optimum temp. for seed storage was , and high germination rate was maintained for 350 days. However, for stratification condition or at room temperature, germination was significantly reduced as storage time increased Optimum treatment of plant growth regulators was soaking in 250 mg/L for 1 hr. The priming treatment with 50 mM at for two days improved the seed germination with 10% compared to non-treated control. The treatment of 20% NaOCl for 3 hr. improved the seed germination rate up to 10% and 1 day ahead.
- Published
- 2014
32. Preparation and structural study of fully dehydrated, highly Mg2+-exchanged zeolite Y (FAU, Si/Al = 1.56) from undried methanol solution
- Author
-
Hu Sik Kim, Sang June Choi, and Woo Taik Lim
- Subjects
Hexagonal prism ,Ion exchange ,Mechanical Engineering ,Solvent ,Crystal ,chemistry.chemical_compound ,Crystallography ,chemistry ,Mechanics of Materials ,Sodalite ,Molecule ,General Materials Science ,Methanol ,Zeolite - Abstract
Single-crystal of fully dehydrated, Mg2+-exchanged zeolite Y, |Mg34.5Na6|[Si117Al75O384]-FAU (Si/Al = 1.56), was successfully prepared from undried methanol solution (water concentration 0.02 M). A crystal of Na-Y was treated with 0.05 M MgCl2 ·6H2O in the solvent at 333 K, followed by vacuum dehydration at 723 K and 1 × 10−6 Torr for 2 days. Its structure was determined by single-crystal synchrotron X-ray diffraction techniques, in the cubic space group $$Fd\overline{3} m$$ at 100 K. It was refined to the final error indices R 1/wR 2 = 0.0587/0.2210 with 1,294 reflections for which F o > 4σ(F o). In the structure of |Mg34.5Na6|[Si117Al75O384]-FAU, 34.5 Mg2+ ions per unit cell are found at four different crystallographic sites: 15 per unit cell are located at site I at the center of the hexagonal prism [Mg–O = 2.216(2) A], two are at site I’ in the sodalite cavity near the hexagonal prism [Mg–O = 2.20(3) A], only one is located at site II’ in the sodalite cavity [Mg–O = 2.197(23) A], and the remaining 16.5 are at site II near single 6-oxygen rings in the supercage [Mg–O = 2.103(3) A]. The residual 6 Na+ ions per unit cell are found at site II [Na–O = 2.218(7) A]. No water molecules are found in this structure.
- Published
- 2014
33. Economic Impacts of Abnormal Climate on Total Output of Red Pepper
- Author
-
Woon-Won Kim, Jae-Hwan Cho, Jeong-Min Suh, Woo Taik Lim, Hyun-Moo Shin, Chang-Oh Hong, and Jum-Soon Kang
- Subjects
Displacement model ,Yield (finance) ,Price change ,Pepper ,Production (economics) ,Environmental science ,Total revenue ,Climate change ,Economic impact analysis ,Agricultural economics - Abstract
The purpose of this article is analyzing the economic impacts of abnormal climate on total revenue of red pepper in Korea, with employing the equilibrium displacement model. Our simulation results show the rate of yield change, price change, and total revenue change according to the climate change scenarios. In th case of by RCP 8.5 Scenario, red pepper production volume would be expected to decrease by 77.2% compared to 2012 while price increasing by 29.6%. As a result, total revenue to be returned to farmers would be reduced by 47.6% than it was in 2012. In contrast, total revenue would be expected to decline by 29.6% according to RCP 4.5 scenario.
- Published
- 2014
34. Characterization of Natural Zeolite for Removal of Radioactive Nuclides
- Author
-
김후식 ( Hu Sik Kim ), 박원광 ( Won Kwang Park ), 임우택 ( Woo Taik Lim ), and 박종삼 ( Jong Sam Park )
- Abstract
국내 경상북도 포항 및 경주지역에서 채취한 4종의 천연 제올라이트를 X-선 회절, X-선 형광분석, 열시차 분석, 열중량 분석 및 양이온교환능 분석을 통해 특성분석을 수행하였다. 이들 제올라이트의 주성분은 구룡포(Ku)는 휼란다이트, 포항(Po)은 클라이놉틸로라이트와 석영이 혼합된 모데나이트이며 양북A (Ya-A)는 휼란다이트, 클라이놉틸로라이트 및 석영이 함유된 일라이트이며, 양북B (Ya-B)는 휼란 다이트와 클라이놉틸로라이트가 혼합된 일라이트이다. 4종의 제올라이트는 Si, Al, Na, K, Mg, Ca, Fe을 함유하고 있었다. 구룡포 (Ku) 제올라이트의 양이온 교환능이 다른 지역의 제올라이트 보다 높게 나타났다. Cs 및 Sr의 흡착실험은 25 ℃에서 수행하였으며, 흡착자료를 기초로 Langmuir와 Freundlich 흡착 등온식에 대한 적합성을 평가하였다. 흡착공정은 Langmuir 흡착 등온식이 잘 맞았으며, 양북 A 제올라 이트가 다른 제올라이트 보다 Cs+ 및 Sr2+ 이온의 제거에 가장 효과적임을 보여주었다.
- Published
- 2014
35. Preparation of excessively Ni2+-exchanged zeolite Y (FAU, Si/Al = 1.70) and its single-crystal structure
- Author
-
Man Park, Sung Man Seo, Dong Yong Chung, and Woo Taik Lim
- Subjects
Aqueous solution ,Chemistry ,Mechanical Engineering ,Inorganic chemistry ,Crystal structure ,Ion ,Crystal ,chemistry.chemical_compound ,Crystallography ,Mechanics of Materials ,Hydroxide ,General Materials Science ,Qualitative inorganic analysis ,Zeolite ,Single crystal - Abstract
A single crystal of excessively Ni2+-exchanged zeolite Y (FAU, Si/Al = 1.70) was prepared by exchange of |Na71|[Si121Al71O384]-FAU with an aqueous stream 0.05 M Ni(NO3)2 at 293 K and pH 4.9, followed by vacuum evacuation at room temperature and 1.3 × 10−4 Pa. Its crystal structure was determined by single-crystal synchrotron X-ray diffraction techniques in the cubic space group Fd $$\overline{ 3}$$ m and was refined to the final error indices R 1/wR 2 = 0.0554/0.1557 for |Ni24.7(NiOH)12.1(Ni2O(OH)2)4.8(Ni4AlO4)1.7Na17.0(H3O)6.9|[Si117Al75O384]-FAU. Crystal has about 53 Ni2+ ions per unit cell, indicating the uptake of excess Ni(OH)2, perhaps as NiOH+ ions. Some dealumination of the framework occurred during Ni2+ exchange. In this structure, Ni2+ ions occupy sites I, I′, II′, II, and III′. The residual Na+ ions are found at sites II′ and II. Due to the low pH of the Ni2+ exchange solution, some H3O+ ions are observed. Nonframework oxygen atoms as oxide and hydroxide ions and orthoaluminate coordinate to some of Ni2+ ions to give NiOH+, Ni2O(OH)2, and Ni4AlO4 3+ groups.
- Published
- 2014
36. The Effect of Co2+-Ion Exchange Time into Zeolite Y (FAU, Si/Al = 1.56): Their Single-Crystal Structures
- Author
-
Sung Man Seo, Woo Taik Lim, Hu Sik Kim, Jeong Min Suh, and Dong Yong Chung
- Subjects
Diffraction ,Ion exchange ,Chemistry ,General Chemistry ,Crystal structure ,medicine.disease ,Synchrotron ,law.invention ,Ion ,Crystallography ,law ,medicine ,Dehydration ,Zeolite ,Single crystal - Abstract
K for 6 h, 12 h, and 18 h, respectively, followed by vacuum dehydration at 673 K. Their single-crystal structures were determined by synchrotron X-ray diffraction techniques in the cubic space group Fd3m at 100(1) K. They were refined to the final error indices R1/wR2 = 0.0437/0.1165, 0.0450/0.1228, and 0.0469/0.1278, respectively. Their unit-cell formulas are |Co29.1Na11.8H5.0|[Si117Al75O384]-FAU, |Co29.8Na11.0H4.4|[Si117Al75O384]-FAU, and |Co30.3Na9.5H4.9|[Si117Al75O384]-FAU, respectively. In all three crystals, Co 2+ ions occupy sites I, I' and II; Na + ions are also at site II. The tendency of Co 2+ exchange slightly increases with increasing contact time as Na + content and the unit cell constant of the zeolite framework decrease.
- Published
- 2014
37. The Economic Impacts of Abnormal Climate on Fall Chinese Cabbage Farmers and Consumers
- Author
-
Jeong-Min Suh, Sang-Gyu Lee, Chang-Oh Hong, Jum-Soon Kang, Woo Taik Lim, Hyun-Moo Shin, and Jae-Hwan Cho
- Subjects
Consumption (economics) ,Ecology ,Displacement model ,Yield (finance) ,Farm income ,Economics ,Climate change ,Economic impact analysis ,Agricultural economics - Abstract
The purpose of this article is analyzing the economic impacts of abnormal climate on fall chinese cabbage farmers and consumers in Korea, with employing the equilibrium displacement model. Our results show that there were little difference in gross farm income, even though there were significant yield reductions due to abnormal climate changes. However periodic occurrences of abnormal climates caused serious damage to consumption levels which had declined by 10.6~17.1 percent with higher prices by 15.3~24.6 percent than normal climate years since 1990.
- Published
- 2013
38. Predicted Optimum Efficiency due to Changes in the Design Parameters of the Small Electrostatic Precipitator
- Author
-
Chool-Jae Park, Jeong-Min Suh, Kum-Chan Choi, Woo Taik Lim, Pyong-In Yi, Moon-Sub Jung, and Jeong-Ho Park
- Subjects
Indoor air quality ,Nuclear engineering ,Electric field ,Electrode ,Environmental engineering ,Environmental science ,Electrostatic precipitator ,Volumetric flow rate ,Voltage - Abstract
The result of a small electrostatic precipitator which is in order to decrease indoor air pollution for optimal efficiency was shown as follows. Although the closer distance between the discharge electrode and dust collecting electrode shows the better throughput efficiency by forming strong electrostatic Field, it does not have profound impact in case of optimal dust collecting area. G.P(gas passage) which is the distance from dust collecting electrode to dust collecting electrode is a crucial factor to decide dust collecting efficiency. The narrower distance of G.P shows the better throughput efficiency whereas it decreases when the distance is too narrow since sparks ensue by increasing the capacity of electrostatic charging system 5 mm regards as optimal efficiency in this experiment. Although the higher voltage shows the higher dust collecting efficiency overall, the experiment was not able to keep performing since the sparks which decrease dust collecting efficiency ensue over 40 kV. The efficient and safe voltage state is considered 3.6 kV in this experiment. The most crucial factor for dust collecting efficiency of an electrostatic precipitator which is in order to decrease indoor air pollution is applied voltage. In addition, optimal raw gas flow rate(2.4 m/sec) is more important factor than the excessive increase of dust collecting area.
- Published
- 2013
39. Li+-exchanged Zeolites X and Y (FAU) from Undried Formamide Solution
- Author
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Jong Sam Park, Jeong Min Suh, Hu Sik Kim, Jeong Jin Kim, and Woo Taik Lim
- Subjects
Formamide ,Ion exchange ,Chemistry ,chemistry.chemical_element ,medicine.disease ,Ion ,Crystal ,Crystallography ,chemistry.chemical_compound ,Torr ,medicine ,Lithium ,Dehydration ,Zeolite - Abstract
Two single-crystals of fully dehydrated, partially Li+-exchanged zeolites X (Si/Al = 1.09, crystal 1) and Y (Si/Al = 1.56, crystal 2), were prepared by flow method using 0.1 M LiNO₃ at 393 K for 48 h, respectively, followed by vacuum dehydration at 673 K and 1 × 10 -6 Torr. Their structures were determined by single-crystal X-ray diffraction techniques in the cubic space group Fd3and Fd3m at 100(1) K for crystals 1 and 2, respectively. They were refined to the final error indices R₁/wR₂ = 0.065/0.211 and 0.043/0.169 for crystals 1 and 2, respectively. In crystal 1, about 53 Li+ ions per unit cell are found at three distinct positions; 9 at site I’, 19 at another site I’, and the remaining 25 at site II. The residual 25 Na+ ions occupy three equipoints; 2 are at site I, 7 at site II, and 16 at site III’. In crystal 2, about 31 Li+ ions per unit cell occupy sites I’ and II with occupancies at 22 and 9, respectively; 3, 4, 23, and 3 Na+ ions are found at sites I, I’, II, and III’, respectively. The extent of Li+ ion exchange into zeolite X (crystal 1) is higher than that of zeolite Y (crystal 2), ca. 73% and 56% in crystals 1 and 2, respectively.
- Published
- 2013
40. Complete Li+ exchange into zeolite X (FAU, Si/Al = 1.09) from undried methanol solution
- Author
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Hu Sik Kim, Woo Taik Lim, and Sik Young Choi
- Subjects
Ion exchange ,Chemistry ,Mechanical Engineering ,Inorganic chemistry ,chemistry.chemical_element ,Catalysis ,Ion ,Crystal ,Solvent ,Crystallography ,chemistry.chemical_compound ,Mechanics of Materials ,Sodalite ,General Materials Science ,Lithium ,Zeolite - Abstract
Complete exchange of Li+ into zeolite Na-X, |Na92|[Si100Al92O384]-FAU, was accomplished using undried methanol solvent (water concentration 0.02 M). A crystal of Na-X was treated with 0.1 M LiNO3 in the solvent at 333 K, followed by vacuum dehydration at 673 K and 1 × 10−6 Torr for 2 days. Its structure was determined by single-crystal synchrotron X-ray diffraction techniques, in the cubic space group $$ Fd\overline{3} $$ at 100(1) K. The 92 Li+ ions per unit cell are found at three different crystallographic sites. The 32 Li+ ions occupy at site I’ in the sodalite cavity: these Li+ ions are recessed 0.28 A into the sodalite cavity from their 3-oxygens plane [Li–O = 1.903(5) A and O–Li–O = 117.8(3)°]. Another 32 Li+ ions are found at site II in the supercage, being recessed 0.26 A into the supercage [Li–O = 1.968(5) A and O–Li–O = 118.3(3)°]. The remaining 28 Li+ ions are located at site III in the supercage [Li–O = 2.00(8) A].
- Published
- 2013
41. Synthesis and single-crystal structure of lead oxide nanoclusters in zeolite Y, |Pb 15.5 2+ (Pb4O4(Pb 16/19 2+ Pb 3/19 4+ )4)4.75|[Si117Al75O384]-FAU
- Author
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Sung Man Seo, Hai Su, Hu Sik Kim, Hyung Joo Lee, and Woo Taik Lim
- Subjects
Aqueous solution ,Ion exchange ,Chemistry ,Mechanical Engineering ,Inorganic chemistry ,Crystal structure ,Nanoclusters ,Ion ,Crystallography ,chemistry.chemical_compound ,Mechanics of Materials ,Sodalite ,General Materials Science ,Zeolite ,Single crystal - Abstract
A single crystal of excessively Pb2+-exchanged zeolite Y (|Pb 15.5 2+ (Pb4O4(Pb 16/19 2+ Pb 3/19 4+ )4)4.75|[Si117Al75O384]-FAU) was prepared by exchange of Na–Y (|Na75|[Si117Al75O384]-FAU, Si/Al = 1.56) with an aqueous stream 0.05 M Pb(C2H3O2)2 at 294 K, followed by vacuum dehydration at 1 × 10−6 Torr and 693 K. Its structure was determined at 100 K, by X-ray diffraction techniques in the cubic space group Fd $$ \overline{3} $$ m and was refined to the final error indices R 1/wR 2 = 0.0639/0.1323. About 53.5 Pbn+ ions per unit cell occupy three different equipoints; 26 are at site I′, 19 are at site II, and the remaining 8.5 are at another site II. Three Pb4+ ions at some of the positions must have higher oxidation states due to elevated dehydration temperature; Pb(IIa) is supposed to coexist with Pb2+ and Pb4+ ions assuming the charge balance of the zeolite framework. A distorted Pb4O4 cube, alternating Pb2+ at Pb(I′) and O2− at O(5), coordinates with four Pb2+ and/or Pb4+ ions through its oxygen atoms to give a [Pb 4 2+ O 4 2− (Pb 16/19 2+ Pb 3/19 4+ )4]176/19+ cluster in 4.75 of eight sodalite cavities per unit cell in zeolite Y.
- Published
- 2013
42. Partially Dehydrated Fully Zn2+-exchanged Zeolite Y (FAU, Si/Al = 1.70) and Its Structure
- Author
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Sung Man Seo, Seok-Hee Lee, Woo Taik Lim, and Young Hun Kim
- Subjects
chemistry.chemical_compound ,Crystallography ,Ion exchange ,Chemistry ,Sodalite ,Molecule ,chemistry.chemical_element ,Crystal structure ,Zinc ,Ring (chemistry) ,Zeolite ,Ion - Abstract
The crystal structure of partially dehydrated fully Zn 2+ -exchanged zeolite Y was determined by X-ray diffraction techniques in the cubic space group Fd3m at 294(1) K and refined to the final error indices R₁/wR₂ = 0.035/0.119 for |Zn 35.5 (H₂O) 13 |[Si 121 Al 71 O 384 ]-FAU. About 35.5 Zn 2+ ions per unit cell are found at six distinct positions; sites I, I’, a second I’, II’, II, and a second II. In sodalite cavities, the 11 water molecules coordinate to Zn(I’b) and/or Zn(II’) ions; each of two H₂O bonds to a Zn(IIb) in supercages. Two different Zn 2+ positions near 6-oxygen ring are due to their Si-Al ordering in tetrahedral site by Si/Al ratio leading to the different kinds of 6-rings.
- Published
- 2013
43. The Impacts of High Temperature and Heavy Precipitation Amount on Winter Chinese Cabbage Yields
- Author
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Jae-Hwan Cho, Chang-Oh Hong, Jum-Soon Kang, Jeong-Min Suh, Sang-Gyu Lee, Woo Taik Lim, and Kyung-Ho Jin
- Subjects
Agronomy ,Yield (wine) ,Greenhouse gas ,Environmental science ,Climate change ,Precipitation - Abstract
The purpose of this article is analyzing the impacts of climate change on winter chinese cabbage yield in Korea, with employing a panel data regression model. Our results show that there is a negative impacts of high temperature and precipitation amount on winter chinese cabbage yields. Especially high temperature and rainfall in September cause serious damage to winter chinese cabbage yield. According to the reduction schedule on greenhouse gas emission(RCP 4.5 scenario.), winter chinese cabbage yield would be 7.7% lower than it is, for reasons of high temperature and rainfall damages by the end of 21st century.
- Published
- 2013
44. Single-Crystal Structure of |Li50Na25|[Si117Al75O384]-FAU
- Author
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Jeong Min Suh, Woo Taik Lim, Hu Sik Kim, and Jum Soon Kang
- Subjects
Aqueous solution ,Materials science ,Ion exchange ,chemistry.chemical_element ,Ion ,chemistry.chemical_compound ,Crystallography ,chemistry ,Chemistry (miscellaneous) ,Torr ,Sodalite ,Chemical Engineering (miscellaneous) ,Lithium ,Zeolite ,Single crystal - Abstract
The single-crystal structure of fully dehydrated partially -exchanged zeolite Y, -FAU, was determined by single-crystal synchrotron X-ray diffraction techniques in the cubic space group at 100(1) K. Ion exchange was accomplished by flowing stream of 0.1 M aqueous for 2 days at 293 K, followed by vacuum dehydration at 623 K and Torr for 2 days. The structure was refined using all intensities to the final error indices (using only the 801 reflections with ( > ) . The 50 ions per unit cell are found at three different crystallographic sites. The 19 ions occupy at site I' in the sodalite cavity: the ions are recessed 0.30 into the sodalite cavity from their 3-oxygens plane (Li-O = 1.926(5) and ). The 20 ions are found at site II in the supercage, being recessed 0.23 into the supercage (Li-O = 2.038(5) and ). Site III' positions are occupied by 11 ions: these ions bind strongly to one oxygen atom (Li-O = 2.00(8) ). About 25 ions per unit cell are found at four different crystallographic sites: 4 ions are at site I, 5 at site I', 12 at site II, and the remaining 4 at site III'.
- Published
- 2013
45. Single-Crystal Structures of Li+-exchanged Zeolite X (FAU, Si/Al = 1.09) from Aqueous Solution Depends on Ion-exchange Temperatures at 293 and 333 K
- Author
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Woo Taik Lim, Hu Sik Kim, and Seong Oon Ko
- Subjects
Crystal ,Crystallography ,Aqueous solution ,chemistry ,Ion exchange ,Torr ,chemistry.chemical_element ,Lithium ,General Chemistry ,Zeolite ,Single crystal ,Ion - Abstract
Two single crystals of fully dehydrated partially -exchanged zeolite X were prepared by the exchange of Na-X, (Si/Al = 1.09), with using aqueous 0.1 M at 293 (crystal 1) and 333 K(crystal 2), followed by vacuum dehydration at 623 K and Torr for 2 days. Their structures were determined by single-crystal synchrotron X-ray diffraction techniques in the cubic space group at 100(1) K. Their structures were refined using all intensities to the final error indices (using the 1281 and 883 reflections for which ( > ) = 0.075/0.244 and 0.074/0.223 for crystals 1 and 2, respectively. Their compositions are seen to be -FAU and -FAU, respectively. In crystal 1, 17 ions per unit cell are at site I', 15 another site I', 30 at site II, and the remaining 16 at site III; 2 ions are at site II and the remaining 4 at site III'. In crystal 2, 32 and 30 ions per unit cell fill sites I' and II, respectively, and the remaining 25 at site III'; 2 and 3 ions are found at sites II and III', respectively. The extent of exchange increases slightly with increasing ion exchange temperature from 93% to 95%.
- Published
- 2012
46. Location of Na+Ions in Fully Dehydrated Na+-saturated Zeolite Y (FAU, Si/Al = 1.56)
- Author
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Hu Sik Kim, Hai Su, Sung Man Seo, Woo Taik Lim, Ghyung Hwa Kim, Jeong Min Suh, and Seong Oon Ko
- Subjects
Ion exchange ,Chemistry ,Sodium ,Inorganic chemistry ,chemistry.chemical_element ,General Chemistry ,Microporous material ,Faujasite ,engineering.material ,Ion ,Adsorption ,Aluminosilicate ,engineering ,Zeolite - Abstract
Pohang Accelerator Laboratory, Accelerator Division, Beam Operation Team, Pohang 790-784, KoreaReceived March 6, 2012, Accepted May 14, 2012Key Words : Sodium, Structure, Faujasite, Ion exchange, Zeolite YZeolites are natural or synthetic crystalline, microporous,aluminosilicate materials with well-defined structures andunique characteristics. Faujasite-type zeolites have beenwidely used in range of applications as ion exchangers, cata-lysts, and adsorbents due to their industrial importance.
- Published
- 2012
47. The Prediction of Optimal Pulse Pressure Drop by Empirical Static Model in a Pulsejet Bag Filter
- Author
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Jeong-Ho Park, Jeong-Min Suh, Jae-Hwan Cho, Woo Taik Lim, and Jum-Soon Kang
- Subjects
Pressure drop ,geography ,geography.geographical_feature_category ,Materials science ,Correlation coefficient ,Pulsejet ,Drop (liquid) ,Analytical chemistry ,Mechanics ,Coke ,Total pressure ,Inlet ,Pulse pressure - Abstract
A pilot-scale pulse-jet bagfilter was designed, built and tested for the effects of four operating conditions (filtration velocity, inlet dust concentration, pulse pressure, and pulse interval time) on the total system pressure drop, using coke dust from a steel mill factory. Two models were used to predict the total pressure drop according to the operating conditions. These model parameters were estimated from the 180 experimental data points. The empirical model (EM) with filtration velocity, areal density, inlet dust concentration, pulse interval time and pulse pressure shows the best correlation coefficient (R=0.971) between experimental data and model predictions. The empirical model was used as it showed higher correlation coefficient (R=0.971) compared to that of the Multivariate linear regression(MLR) (R=0.961). The minimum pulse pressure predicted by empirical model (EM) was 5kg/ ㎠ . Key Words : Pulse-jet bagfilter, Coke dust, Pulse pressure, Pressure drop, Empirical model
- Published
- 2012
48. Single-crystal Structure of Cd2+-exchanged Zeolite Y (FAU, Si/Al = 1.56), |Cd27.5(Cd8O4)2.5|[Si117Al75O384]-FAU
- Author
-
Woo Taik Lim and Sung Man Seo
- Subjects
Crystal ,chemistry.chemical_compound ,Aqueous solution ,Ion exchange ,Chemistry ,Inorganic chemistry ,Analytical chemistry ,Sodalite ,Molecule ,General Chemistry ,Zeolite ,Molecular sieve ,Single crystal - Abstract
Zeolite framework contains channels and windows and interconnected voids which are occupied by the cations and water molecules. The cations are quite mobile and may usually be exchanged by other cations. Ion exchange is the most important method for the modification of the physical and chemical properties of zeolites for use as catalysts, sorbents, and molecular sieves. The results of ion exchange into zeolites from aqueous solution are usually not simple. Often only a fraction of the original cations can be replaced, and attempts to overcome this may reveal a relatively sharp upper limit to exchange. When acetate salt of metal cations dissolves in water for exchange solution, metal hydroxide ions occurred. It can be exchanged for Na ions into zeolite framework, leading to over exchange. The catalytic activity of Cd-exchanged zeolite Y for the formation of acetonitrile was studied for comparison with activated alumina (Al2O3) and also examined for the formation of acetonitrile from ethane and ammonia. Its catalytic activity had much higher than that of Al2O3. It was found to be essentially inactive for the formation of acetonitrile from ethylamine. When zeolite Y (Si/Al = 1.69) was ion exchanged in aqueous stream 0.05 M in Cd (0.025 M Cd(NO3)2 and 0.025 M Cd(C2H3O2)2) for 5 days and dehydrated at 723 K and 2 × 10 Torr for 2 days, the resulting composition, |Cd27.5(Cd8O4)2| [Si121Al71O384]-FAU, indicated that eight molecules of Cd(OH)2 had been imbibed per unit cell. With eight nonframework oxides, two Cd8O4 clusters had formed per unit cell. It was stated that the ability of Cd ions to hydrolyze at pH 7 facilitated this process, as did the ability of the sodalite unit to host and stabilize Cd4(OH)4 clusters. This study was done to investigate the behavior of Cd in Cd-exchanged zeolite Y (Si/Al = 1.56) prepared at high ion-exchange temperature (353 K), with the expectation of forming more cadmium oxide cluster, Cd8O4. Synchrotron X-ray diffraction data were collected at 100 (1) K using an ADSC Quantum 210 detector at Beamline 6B MXI at the Pohang Light Source. Crystal evaluation and data collection were done using λ = 0.90000 A radiation with a detector-to-crystal distance of 60 mm. Preliminary cell constants and an orientation matrix were determined from 72 sets of frames collected at scan intervals of 5 with an exposure time of 1 second per frame. The basic scale file was prepared using the program HKL 2000. The reflections were successfully indexed by the automated indexing routine of the DENZO program. The 87,989 reflections were harvested by collecting 144 sets of frames with 5 scans and an exposure time of 1 second per frame. These highly redundant data sets were corrected for Lorentz and polarization effects, and (negligible) corrections for crystal decay were also applied. The cubic space group was determined by the program XPREP. The summary of the experimental and crystallographic data is presented in Table 1. Full-matrix least-squares refinement (SHELXL97) was done on Fo using all data. Refinement was initiated with the atomic parameters of the framework atoms [(Si,Al), O(1), O(2), O(3), and O(4)] in dehydrated |Tl75| [Si117Al75O384]-FAU. Initial refinement used anisotropic thermal parameters and Fd3m
- Published
- 2012
49. Single-crystal Structure of Partially Dehydrated Partially Mg2+-exchanged Zeolite Y (FAU), |Mg30.5Na14(H2O)2.5|[Si117Al75O384]-FAU
- Author
-
Seong Oon Ko, Woo Taik Lim, and Hu Sik Kim
- Subjects
Crystallography ,chemistry.chemical_compound ,Materials science ,Ion exchange ,chemistry ,Magnesium ,Sodalite ,chemistry.chemical_element ,Molecule ,General Chemistry ,Zeolite ,Single crystal ,Ion - Abstract
The single-crystal structure of partially dehydrated partially -exchanged zeolite Y, []-FAU per unit cell, = 25.5060(1) , dehydrated at 723 K and Pa, has been determined by single-crystal X-ray diffraction techniques in the cubic space group Fd m at 100(1) K. The structure was refined using all intensities to the final error indices (using only the 561 reflections with > ) = 0.0377 (Based on F) and = 0.1032 (Based on ). About 30.5 ions per unit cell are found at four different crystallographic sites. The 14 ions occupy at site I at the center of double 6-ring (Mg-O = 2.231(3) , O-Mg-O = and ). Four ions are found at site I' in the sodalite cavity; the ions are recessed 1.22 into the sodalite cavity from their 3-oxygen plane (Mg-O = 2.20(3) and O-Mg-O = ). Site II' positions (opposite single 6-rings in the sodalite cage) are occupied by 2.5 ions, each coordinated to an molecule (Mg-O = 2.187(20) and O-Mg-O = ). The 10 ions are nearly three-quarters filled at site II in the supercage, being recessed 0.12 into the supercage (Mg-O = 2.123(4) A and O-Mg-O = ). About 14 ions per unit cell are found at one crystallographic site; the ions are located at site II in the supercage (Na-O = 2.234(7) and O-Mg-O = ).
- Published
- 2011
50. Synthesis of Single Crystalline Analcime and Its Single-crystal Structure, |Na0.94(H2O)|[Si2.06Al0.94O6]-ANA: Determination of Cation Sites, Water Positions, and Si/Al Ratios
- Author
-
Sung-Man Seo, Seong-Oon Ko, Woo Taik Lim, and Jeong-Min Suh
- Subjects
Diffraction ,Crystallography ,Aqueous solution ,Analcime ,Chemistry (miscellaneous) ,Chemistry ,engineering ,Chemical Engineering (miscellaneous) ,Orthorhombic crystal system ,engineering.material ,Chemical composition ,Single crystal ,Ion - Abstract
Large colorless single crystals of analcime with diameters up to 0.20 mm have been synthesized from gels with the composition of : : 8.02NaOH : : 5.00TEA. The fully -exchanged analcime have been prepared with aqueous 0.1 M NaCl (pH adjusted from 6 to 11 by dropwise addition of NaOH). The single-crystal structure of hydrated -ANA per unit cell, a=13.703(3) , has been determined by single-crystal X-ray diffraction technique in the orthorhombic space group Ibca at 294 K. The structure was refined using all intenties to the final error indices (using only the 1,446 reflections for which > = 0.054/0.143. About 15 ions are located at three nonequivalent positions and octahedrally coordinated. The chemical composition is . The Si/Al ratio of synthetic analcime is 2.19 determined by the occupations of cations, 14.79, in the single-crystal determination work.
- Published
- 2011
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