• 제목/요약/키워드: Cation-exchange-reaction

검색결과 128건 처리시간 0.032초

A Study on the Preparation of Carboxylated Polysulfone/MeVpI-DVB Membranes and Its Characteristics (Carboxylated Polysulfon/MeVpl-DVB 막의 제조와 특성에 관한 연구)

  • 김관식;전경용;조영일
    • Membrane Journal
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    • 제5권1호
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    • pp.26-34
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    • 1995
  • In this study, polysulfone was carboxylated(CPSf), as a method of introducing carboxyl group to polymer main chain using direct lithiation reaction. Then, poly(1-alkyl-4-vinylpyridinium iodide-co-divinylbenzene) (MeVpI-DVB) containing pyridinium cation which has an anion selectivity as a fixed carrier was synthesized. And polymer membranes were prepared by mixing CPSf and MeVpI-DVB. Characteristics and permeation of membranes were investigated. As a result of synthesizing CPSf/MeVpI-DVB, blend was formed, not new copolymer. As the content of CPSf amount increasing, thermal stability of membranes was increasing. Ion exchange capacity was 1.0~1.8(meq/g dry mem.) and water content was 0.16~0.26(g $H_2{O}$)/g dry mem.) and fixed ion concentration was 6.4~7.3(meq/g $H_2{O}$) in synthetic membranes. The $Cl^-$ flux showed an increase due to the increase of CPSf content.

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Preparation and Performance of Synthetic Organo-beidellite (유기 바이델라이트의 합성 및 거동 연구)

  • Ryu, Gyoung-Won;Jang, Young-Nam;Cho, Sung-Jun;Choi, Sang-Hoon
    • Journal of the Mineralogical Society of Korea
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    • 제19권2호
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    • pp.123-128
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    • 2006
  • Beidellite, a member of the dioctahedral smectite group, was synthesized hydrothermally from dickite. Organophilic [DEACOOH]-beidellite intercalation complex was formed by the cation exchange reaction between synthetic Na-beidellite and [DEACOOH]Br. The products dried in high vacuum were treated with various organic solvent such as methanol, ethanol, acetone, ether, acetonitrile and caprolactam in order to determine the swelling behaviour of the prepared complexes. After drying under high vacuum, basal spacing of [DEACOOH]-beidellite shows 15.1 ${\AA}$, and it changed to 19.4, 29.9, 15.9, 16.8, 14.8, 26.5 and 14.8 ${\AA}$ under distilled water, methanol, ethanol, acetone, ether, acetonitrile and caporlactam, respectively. Especially, the characteristics of the intercalation complexes and their swelling behavior of the synthetic beidellite and natural montmorillonite were compared.

Physicochemical Properties of Artificial Soil Formulated by Blending Calcined Clay and Coconut Peat and its Effect on Plant Growth (소성 점토다공체 및 코코넛 피트를 혼합한 인공토양의 물리화학적 특성과 식물생육에 미치는 영향)

  • 허근영;강호철;김인혜;심경구
    • Journal of the Korean Institute of Landscape Architecture
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    • 제30권5호
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    • pp.107-115
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    • 2002
  • This study was carried out to compare artificial soil formulated by blending calcined clay and coconut peat with perlite, then to evaluate this soil as a perlite substitute for use as an artificial planting medium. To achieve this, a determination of the physico-chemical properties and it's effect on plant growth were conducted by comparing those with large perlite grains and small grains. The results are summarized as follows: 1) The bulk density was 0.41g/㎤. This density was lower than that of field soil, but higher than that of large perlite grain(0.23g/㎤) and small grain(0.25g/㎤). The porosity, field capacity, and saturated hydraulic conductivity were 71.3%, 49.2%, and 3.8$\times$10-2cm/s, respectively. The air-permeability, water holding capacity, and drainage were better than or equal to that both large and small perlite grain. 2) It was near-neutral in reaction(pH=6.6). It had a high organic carbon content(65.8g/kg) and a low available phosphoric acid content(84.7mg/kg). It was similar to crop soil in cation exchange capacity(11.4cmol/kg). It had a low exchangeable calcium content(0.71cmol/kg), a low exchangeable magnesium content(0.68cmol/kg), a high exchangeable potassium content(2.54cmol/kg), and a high exchangeable sodium content(1.12cmol/kg). Except for the exchangeable potassium and sodium content, the chemical properties were better than or equal to both large and small grain perlite. The excessive exchangeable potassium or sodium content will inhibit plant growth. 3) In Experiment 1, the plant growth tended to be higher compared to that of large and small perlite gains. But in Experiment 2, it tended to be lower. This might be linked to the excessive exchangeable potassium or sodium content. 4) It could be considered as a renewable perlite substitute for greening of artificial soil. But, it would be necessary to leach the excessive exchangeable potassium or sodium to avoid the risk of inhibiting plant growth.

Flocculation Characteristics of the Polycondensate of 1-Butylamine and Epichlorohydrin(PBE) (1-부틸아민과 에피클로로히드린의 축합체인 PBE의 응집작용 특성)

  • Kim, Hag-Seong;Joo, Duk-Jong
    • Applied Chemistry for Engineering
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    • 제9권4호
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    • pp.569-573
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    • 1998
  • A water soluble polymer, polycondensate of 1-butylamine and epichlorohydrin (PBE), was synthesized by condensation of 1-butylamine and epichlorohydrin. The characteristics of PBE were determined by IR spectroscopy, low angle light scattering measurement, and $\zeta$ potential measurement. Its interactions with colloidal bentonite particles in aqueous medium were also studied. The results of the studies are as follows : PBE is a cationic polyelectrolyte carrying tertiary ammonium ions on its backbone. The average molecular weight of PBE is found to be about 1,600. The adsorption of PBE on the colloidal bentonite particles are well described with Langmuir adsorption isotherm. As the amounts of PBE adsorbed on the bentonite particles increase, the $\zeta$ potential of the particles changes its sign from negative to positive. This inversion of charge confirms that PBE is cationic in nature. The adsorption of PBE onto the bentonite particles was found to occur through cation exchange reaction. It has been shown that PBE has flocculation effects on the colloidal suspension of bentonite. It has also enhanced effects of filtrability on the digested sludge.

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The Separation of Transglutaminase Produced from Streptomyces mobaraensis and Its Application on Model Food System (Streptomyces mobaraensis로부터 생산되는 transglutaminase 분리 및 모델식품 적용)

  • Yoo, Jae-Soo;Shin, Weon-Sun;Chun, Gie-Tack;Kim, Young-Soo;Jeong, Yong-Seob
    • Korean Journal of Food Science and Technology
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    • 제35권2호
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    • pp.260-265
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    • 2003
  • Transglutaminase (TG) was prepared from Streptomyces mobaraensis to improve texture and self-life of food. In preliminary experiments, texture of the dough was not improved due to the interference in microbial TG reaction by proteases present in the crude enzyme. Among the cation exchange resins tested for the removal of proteases, MonoPlus S 100 was the most efficient. Further purification steps with a quaternary ammonia salt resin and gel permeation chromatography effectively removed proteases from crude enzyme. Molecular weight of purified enzyme was about 38,000 on SDS-polyacrylamide gel electrophoresis. Farinograph data showed the addition of purified enzyme to wheat flour gave higher stability and lower weakness values those that of crude enzyme.

Solvent Extraction of Zirconium and Hafnium from Hydrochloric Acid solution by LIX 63 and Cyanex 301 (염산용액(鹽酸溶液)에서 LIX 63 및 Cyanex 301에 의한 지르코늄과 하프늄의 용매추출(溶媒抽出))

  • Min, Soo-Hwan;Lee, Man-Seung
    • Resources Recycling
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    • 제22권6호
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    • pp.19-25
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    • 2013
  • Solvent extraction experiments have been conducted to separate Zr(IV) and Hf(IV) from chloride solutions by using LIX63 and Cyanex301. Zr and Hf were extracted by cation exchange reaction in the pH range from 1 to 4 by the extratants. Since the extraction percentage of the two metals was similar to each other, it was difficult to separate the two metals by using LIX63 or Cyanex301. Use of a mixture of LIX63/TBP or Cyanex301/TBP resulted in antagonism in our experimental ranges. Our data showed that there is some possibility of separating the two metals by the mixture of Cyanex301 and TBP because the extraction percentage of Hf decreased more rapidly than that of Zr as HCl concentration was decreased. The mixture of LIX63 and Cyanex301 had little effect on the separation of the two metals.

Hydrogen Production from Water Electrolysis Driven by High Membrane Voltage of Reverse Electrodialysis

  • Han, Ji-Hyung;Kim, Hanki;Hwang, Kyo-Sik;Jeong, Namjo;Kim, Chan-Soo
    • Journal of Electrochemical Science and Technology
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    • 제10권3호
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    • pp.302-312
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    • 2019
  • The voltage produced from the salinity gradient in reverse electrodialysis (RED) increases proportionally with the number of cell pairs of alternating cation and anion exchange membranes. Large-scale RED systems consisting of hundreds of cell pairs exhibit high voltage of more than 10 V, which is sufficient to utilize water electrolysis as the electrode reaction even though there is no specific strategy for minimizing the overpotential of water electrolysis. Moreover, hydrogen gas can be simultaneously obtained as surplus energy from the electrochemical reduction of water at the cathode if the RED system is equipped with proper venting and collecting facilities. Therefore, RED-driven water electrolysis system can be a promising solution not only for sustainable electric power but also for eco-friendly hydrogen production with high purity without $CO_2$ emission. The RED system in this study includes a high membrane voltage from more than 50 cells, neutral-pH water as the electrolyte, and an artificial NaCl solution as the feed water, which are more universal, economical, and eco-friendly conditions than previous studies on RED with hydrogen production. We measure the amount of hydrogen produced at maximum power of the RED system using a batch-type electrode chamber with a gas bag and evaluate the interrelation between the electric power and hydrogen energy with varied cell pairs. A hydrogen production rate of $1.1{\times}10^{-4}mol\;cm^{-2}h^{-1}$ is obtained, which is larger than previously reported values for RED system with simultaneous hydrogen production.

Reactivity Improvement Characteristics of Weathered Feldspar through Activation Technique (활성기법을 통한 풍화된 장석의 반응성 개선 특성)

  • Cho, Jinwoo
    • Journal of the Korean Geosynthetics Society
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    • 제20권4호
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    • pp.33-41
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    • 2021
  • Feldspar, along with Quartz, are the most frequently produced minerals in Korea; however, the potential value is estimated to be significantly low because of the scarce research on the development and application of material properties, except for their limited use in manufacturing minerals, glass, and paints. In this study, we analyzed the eco-friendly material and reactivity improvement characteristics of weathered feldspar through activation technique. The joint structural features observed on the surface of the weathered feldspar show that the joint arrangements are irregularly distributed, and the cavities are interconnected. Due to the irregularly connected cavities on the surface of weathered feldspar, the reaction area of the weathered feldspar is increased; hence the weathered feldspar is considered as a highly reactive pozzolan material when combined with cement. As a result of applying the thermal, mechanical, and chemical activation techniques to improve the functionality of the weathered feldspar, the cation exchange capacity, density, and uniaxial compression strength characteristics were improved. It is considered that weathered feldspar by these porous characteristics can be used as an eco-friendly construction material with excellent physical and chemical properties.

Investigation of Sorption Reaction of Re(VII) onto HDPy- and HDTMA-modified Bentonite (HDPy 및 HDTMA로 개질된 벤토나이트에 대한 Re(VII)의 흡착반응 분석)

  • Jun-Myung Choi;Junhyuk Ha;Ranyeong Choi;Jun-Yeop Lee
    • Journal of Radiation Industry
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    • 제18권3호
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    • pp.167-171
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    • 2024
  • Technetium-99 (99Tc) is recognized as a critical concern in the disposal of spent nuclear fuel due to its long half-life and remarkable stability, existing predominantly as TcO4- in the natural environment. The anionic form of technetium is highly soluble and mobile, posing significant environmental risks from the viewpoint of nuclear waste management. Thus, developing efficient and cost-effective sorbents for aqueous Tc(VII) is essential for mitigating relevant contamination. In the present work, the adsorption characteristics of Re(VII), a chemical analog of Tc(VII), were investigated using the clay mineral bentonite, modified with two different organic cations: hexadecylpyridinium (HDPy) and hexadecyltrimethylammonium (HDTMA). Sorption experiments were conducted at a liquid-to-solid ratio of 1 g/L with Re(VII) solutions prepared at concentrations from 10-4 mol/L to 10-6 mol/L. The sorption ratio and distribution coefficients were determined with samples collected at reaction times of 10, 50, 100, and 500 minutes after 0.45 ㎛ syringe filtration. In parallel, the modified bentonite samples were further analyzed using the X-ray diffraction (XRD) method to understand the adsorption mechanism of Re(VII) onto the target minerals. According to the quantification analysis results, a rapid equilibrium reaction of aqueous Re(VII) for all modified bentonite samples was identified. Moreover, near-complete adsorption of Re(VII) was observed when the bentonite was modified at 200-400% of its cation exchange capacity (CEC) for both organic cations. For cases of lower modification, the HDTMA-modified bentonite showed relatively higher adsorption efficiency compared with the one modified with HDPy. This result was inferred to be due to the difference in inter-layer spacing based on the characteristics of the organic cations. It is expected that the results obtained through this study will serve as a preliminary case for the synthesis of adsorbents for the retardation of highly mobile anionic radionuclides, such as I and Tc, in the natural environment.

Continuous Decomposition of Ammonia by a Multi Cell-Stacked Electrolyzer with a Self-pH Adjustment Function (자체 pH 조정 기능을 갖는 다단 전해조에 의한 암모니아의 연속식 분해)

  • Kim, Kwang-Wook;Kim, Young-Jun;Kim, In-Tae;Park, Geun-Il;Lee, Eil-Hee
    • Korean Chemical Engineering Research
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    • 제43권3호
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    • pp.352-359
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    • 2005
  • This work has studied the changes of pH in both of anodic and cathodic chambers of a divided cell due to the electrolytic split of water during the ammonia decomposition to nitrogen, and has studied the continuous decomposition characteristics of ammonia in a multi-cell stacked electrolyzer. The electrolytic decomposition of ammonia was much affected by the change of pH of ammonia solution which was caused by the water split reactions. The water split reaction occurred at pH of less than 8 in the anodic chamber with producing proton ions, and occurred at pH of more than 11 in the cathodic chamber with producing hydroxyl ions. The pH of the anodic chamber using an anion exchange membrane was sustained to be higher than that using a cation exchange membrane, which resulted in the higher decomposition of ammonia in the anodic chamber. By using the electrolytic characteristics of the divided cell, a continuous electrolyzer with a self-pH adjustment function was newly devised, where a portion of the ammonia solution from a pHadjustment tank was circulated through the cathodic chambers of the electrolyzer. It enhanced the pH of the ammonia solution fed from the pH-adjustment tank into the anodic chambers of the electrolyzer, which caused a higher decomposition yield of ammonia. And then, based on the electrolyzer, a salt-free ammonia decomposition process was suggested. In that process, ammonia solution could be continuously decomposed into the environmentally-harmless nitrogen gas up to 83%, when chloride ion was added into the ammonia solution.