• Title/Summary/Keyword: hydrogen adsorption

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A study on the Optimization of Activated carbon Adsorbent Preparation condition and Evaluation of Application Supporting of K-Fe-Li ternary metal ions for Improving Adsorption Capacity of Hydrogen Sulfide (H2S) (황화수소(H2S) 흡착성능 증진을 위한 K-Fe-Li 3원계 금속이온물질이 담지된 활성탄 흡착제 제조조건 최적화 및 적용성 평가 연구)

  • Choi, Sung Yeol;Han, Dong hee;Kim, Sung Su
    • Clean Technology
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    • v.25 no.3
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    • pp.189-197
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    • 2019
  • In this study an optimization of the preparation conditions of activated carbon with a ternary metal ion material to treat $H_2S$, which is classified as a representative odor substance, was carried out. For a metal ion material for enhancing the adsorption performance of hydrogen sulfide, performance enhancement was confirmed by combining Li and Fe or a ternary combination (K, Li, Fe) based on KI, which is a substance promoting hydrogen sulfide adsorption performance. Also, it was determined by XRD analysis that the reaction of each active substance with $H_2S$ was because of binding. The adsorption performance increased more than 3 times with heat treatment of the adsorbent with nitrogen compared with heat treatment with air. The maximum adsorption constant ($q_m$) value of the optimum adsorbent was 97.07, which is 6 times higher than that of the existing K-based impregnated activated carbon. It was confirmed that the objective adsorption amount ($0.3g\;g^{-1}$) was secured by an equilibrium between the mass transfer rate and adsorption rate. From the results, it was confirmed that the performance improvement was noticeable even when activated carbon with a reagent grade activated carbon particle size was modified. It was confirmed that the adsorption performance exists at high relative humidity levels of 60 and 100%, and the optimized preparation can be applied to a wet process such as a scrubber downstream.

Effect of Acid Treatments on Hydrogen Storage Behaviors of Ordered Mesoporous Carbons (화학적 산처리가 중기공 탄소체의 수소저장거동에 미치는 영향)

  • Lee, Seul-Yi;Park, Soo-Jin
    • 한국신재생에너지학회:학술대회논문집
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    • 2010.06a
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    • pp.229.1-229.1
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    • 2010
  • We investigated the effect of chemical acid treatments on hydrogen storage behaviors of the ordered mesoporous carbons (MCs). The surface functional groups and specific elements of the MCs were characterized with Fourier Transform Infrared (FT-IR) spectrometry and X-ray photoelectron spectroscopy (XPS). Also, the changes in the surface functional groups of the MCs were quantitatively detected by Boehm's titration method. The structural properties of the MCs were investigated using X-ray diffraction (XRD). The hydrogen adsorption capacity of the MCs was evaluated by means of adsorption isotherms at 77 K/1 bar. The formation of surface functional groups by the acidic treatments could influence on the hydrogen storage capacity of the MCs.

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Hydrogen Storage Behaviors of Carbon Nanotubes/Metal-organic Frameworks-5 Hybrid Composites

  • Park, Soo-Jin;Lee, Seul-Yi
    • Carbon letters
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    • v.10 no.1
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    • pp.19-22
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    • 2009
  • In this work, the hydrogen storage behaviors of carbon nanotubes (CNTs)/metal-organic frameworks-5 (MOF-5) hybrid composites (CNTs/MOF-5) were studied. Hydrothermal synthesis of MOF-5 was conducted by conventional convection heating using 1-methyl-2-pyrrolidone (NMP) as a solvent. Morphological characteristics and average size of the CNTs/MOF-5 were also obtained using a scanning electron microscopy (SEM). The pore structure and specific surface area of the CNTs/MOF-5 were analyzed by N2/77 K adsorption isotherms. The capacity of hydrogen storage of the CNTs/MOF-5 was investigated at 298 K/100 bar. As a result, the CNTs/MOF-5 had crystalline structures which were formed by hybrid synthesis process. It was noted that the CNTs/MOF-5 can be potentially encouraging materials for hydrogen adsorption and storage applications at room temperature.

Surface Reconstruction on Hydrogen Covered W(011) (수소가 흡착된 W(011) 표면의 재구성)

  • 김희봉;최원국;홍사용;황정남;정광호
    • Journal of the Korean Vacuum Society
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    • v.1 no.1
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    • pp.83-87
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    • 1992
  • Rencently, angle-resolved ultraviolet photoemission measurements of the Fermi surface contours for Mo(011) and W(011) are reported. The electron contour of W(011) is expanded upon hydrogen adsorption, which implies that the surface states consisting of electron pockets are shifted to higher binding energy. This phenomena can be explained by the band flattening. We explained here the reconstruction of W(011) surface induced by adsorption of hydrogen in terms of band flattening of surface states with a combination of S. E. Trullinger long range dipole-dipole interaction force and Kohn anomaly.

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($H_{2}S$ Adsorption Capacity of $Na_{2}CO_{3}$ and $KIO_{3}$ Impregnated Activated Carbon (($Na_{2}CO_{3}$$KIO_{3}$ 첨착 왕겨활성탄의 $H_{2}S$ 흡착특성)

  • Kim, Jun-Suk;Kim, Myung-Soo
    • Journal of the Korean Applied Science and Technology
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    • v.19 no.3
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    • pp.213-221
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    • 2002
  • Activated carbons with high surface area of 2,600 $m^{2}/g$ and high pore volume of 1.2 cc/g could be prepared by KOH activation of rice hulls at a KOH:char ratio of 4:1 and $850^{\circ}C$. In order to increase the adsorption capacity of hydrogen sulfide, which is one of the major malodorous component in the waste water treatment process, various contents of $Na_{2}CO_{3}$ and $KIO_{3}$ were impregnated to the rice-hull activated carbon. The impregnated activated carbon with 5 wt.% of $Na_{2}CO_{3}$ showed improved $H_{2}S$ adsorption capacity of 75 mg/g which is twice of that for the activated carbon without impregnation and the impregnated activated carbon with 2.4 wt.% of $KIO_{3}$ showed even higher $H_{2}S$ adsorption capacity of 97 mg/g. The improvement of $H_{2}S$ adsorption capacity by the introduction of those chemicals could be due to the $H_{2}S$ oxidation and chemical reaction with impregnated materials in addition to the physical adsorption of activated carbon.

A Computational Study on the Adsorption Characteristics of Hydrocarbons (Propylene, n-Butane and Toluene) by uing Cation-exchanged ZSM-5 Zeolites

  • Lee, Hyun Chul;Kim, Kyung Min;Choi, Sung Il;Kim, Yong Ha;Woo, Hee Chul;Won, Yong Sun
    • Korean Chemical Engineering Research
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    • v.56 no.6
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    • pp.909-913
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    • 2018
  • A hydrocarbon trap (HT) plays an important role of controlling vehicle emissions in the so-called cold emission period by holding hydrocarbons until three way catalysts (TWCs) are thermally activated. In this study, we have investigated the adsorption characteristics of cation (H, La, K, and Ag)-exchanged ZSM-5 zeolites for hydrocarbons (propylene, n-butane, and toluene) by DFT (density functional theory)-based computational chemistry. Cation exchange is to improve the hydrothermal stability of zeolites and their adsorption capacity, thereby rendering cation-exchanged zeolites promising materials for HT. The idea of cluster approximation makes the calculation of adsorption energies superbly efficient in computation. The results showed that Ag-exchanged ZSM-5 would be the best for the adsorption of all three adsorbates, without often encountered Ag oxidation in experiments. Besides, the hydrothermal stability of La-exchanged ZSM-5 was confirmed from the change of geometrical parameters by cation exchange, and it showed good adsorption capacity for propylene and toluene. Hydrogen-exchanged ZSM-5 was also good for hydrogen adsorption, but had poor hydrothermal stability.

Hydrogen adsorption experiments with IRMOF-3 as a sorbent, and the molecular modeling studies on the functionalized MOFs (IRMOF-3 의 수소 흡착 실험 및 Organic Linker 의 작용기에 따른 분자모델링 연구)

  • Lee, Eungsung;Oh, Youjin;Yoon, Jihye;Kim, Jaheon;Kim, DaeJin;Lee, Tae-Bum;Choi, Seung-Hoon;Lee, Jun;Cho, Sung June
    • Transactions of the Korean hydrogen and new energy society
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    • v.15 no.2
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    • pp.108-118
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    • 2004
  • To find out rational design and synthetic strategies toward efficient hydrogen storage materials, molecular modeling and quantum mechanical studies have been carried out on the MOFs(Metal-Organic Frameworks) having various organic linkers and nanocube frameworks. The calculation results about the free volume ratio, surface area, and electron density variation of the frameworks indicated that the capacity of the hydrogen storage of MOFs was largely dependent on the specific surface area and electron localization around benzene ring rather than the free volume of MOFs. The prediction of the modeling study could be supported by the hydrogen adsorption experiments using IRMOF-1 and -3, which showed more enhanced hydrogen storage capacities of IRMOF-3 compared with the IRMOF-1's at both experimental conditions, 77K, ∠ $H_2$ 1 atm and ambient temperature, ∠ $H_2$ 35 atm.

Effects of activated carbon packing length in PSA process for production of high-purity hydrogen (고순도 수소제조를 위한 PSA 공정에서 활성탄 충전길이 효과)

  • Paik, Eun-gyu;Choi, Min-Ho;Suh, Sung-Sup
    • Clean Technology
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    • v.7 no.2
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    • pp.127-132
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    • 2001
  • The effects of activated-carbon (AC) packing length on the Pressure Swing Adsorption (PSA) performance was investigated for the hydrogen separation from the multicomponent mixture gas. Linear driving force model was used to describe mass transfer between two phase and coupled Langmuir isotherm was used for each component as a nonlinear adsorption isotherm. When two adsorbents with a different adsorption capacity were packed consecutively in one bed, it is very important to determine the packing ratio of zeolite to activated carbon affecting the purity and recovery of the product. The activated carbon packing length in adsorption tower of 120 cm was determinated by the ending point of $CO_2$ contration. The optimum length of an activated carbon layer was 65 cm for production of high-purity hydrogen.

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The Isosteric Heats of Adsorption of Amines on Paraffin and Polyethyleneglycol

  • Sohn Jong Rack;Kim, Jong Taik
    • Journal of the Korean Chemical Society
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    • v.16 no.4
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    • pp.208-213
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    • 1972
  • Isostric heats of adsorption of amines on paraffin and polyethyleneglycol were measured by gas chromatography. Value with polyethyleneglycol were significantly higher than those with paraffin due to the N-H...O bonding. The contribution of C-H...O bonding to the isosoteric heats of adsorption was negligible. The additional heats of adsorption observed as the sample size increased also increased as the number of amino hydrogen atoms decreased. This tendency was more significant with polyethyleneglycol indicating that strong directing force of amino hydrogen of primary and secondary amines to the surface hinder lateral attractive interaction which could be favored with free orientation.

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Study on the development of small-scale hydrogen production unit using steam reforming of natural gas (천연가스 개질 방식 중소형 고순도 수소제조 장치 개발 연구)

  • Seo, Dong-Joo;Chue, Kuck-Tack;Jung, Un-Ho;Park, Sang-Ho;Yoon, Wang-Lai
    • 한국신재생에너지학회:학술대회논문집
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    • 2009.06a
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    • pp.720-722
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    • 2009
  • This work is mainly focused at developing the hydrogen production unit with the capacity of 20 $Nm^3/h$ of high purity hydrogen. At present steam reforming of natural gas is the preferable method to produce hydrogen at the point of production cost. The developed hydrogen production unit composed of natural gas reformer and pressure swing adsorption system. To improve the thermal efficiency of steam reforming reactor, the internal heat recuperating structure was adopted. The heat contained in reformed gas which comes out of the catalytic beds recovered by reaction feed stream. These features of design reduce the fuel consumption into burner and the heat duty of external heat exchangers, such as feed pre-heater and steam generator. The production rate of natural gas reformer was 41.7 $Nm^3/h$ as a dryreformate basis. The composition of PSA feed gas was $H_2$ 78.26%, $CO_2$ 18.49%, CO 1.43% and $CH_4$ 1.85%. The integrated production unit can produce 21.1 $Nm^3/h$ of high-purity hydrogen (99.997%). The hydrogen production efficiency of the developed unit was more than 58% as an LHV basis.

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