• Title/Summary/Keyword: inorganic affinity

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Preparation and Characterization of Polymer Coated BaTiO3 and Polyimide Nanocomposite Films (고분자로 표면 코팅된 BaTiO3와 이를 이용한 폴리이미드 나노복합필름의 제조 및 특성)

  • Han, Seung San;Han, Ji Yun;Choi, Kil-Yeong;Im, Seung Soon;Kim, Yong Seok
    • Applied Chemistry for Engineering
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    • v.17 no.5
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    • pp.527-531
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    • 2006
  • We have prepared organophilic inorganic particles and polyimide (PI) nanocomposite having excellent thermal stability and high dielectric constant that can be used for electronic application such as capacitor. We have chosen barium titanate (BT), a high dielectric constantmaterial and its surface was coated with nylon 6 to improve the affinity with PI. The FT-IR and TEM studies showed that the organophilic inorganic particle (BTN) has a polymer shell with thickness of 5 nm. We have suggested that it is possible to control the thickness of coating surface and also indicated the relationship between the ratio of inside and outside radius of BTN and the weight fraction of BT. The PI nanocomposite films based on poly(amic acid) and BTN were prepared by cyclodehydration reaction. The homogeneous dispersion of BTN in PI matrix was identified by using SEM. We have investigated the effect of BTN content on the coefficient of thermal stability, integral procedural decomposition temperature (IPDT), and dielectric constant of PI nanocomposite films.

Salmonella Typhimurium SL1344 Utilizing Human Transferrin-bound Iron as an Iron Source Regardless of Siderophore-mediated Uptake (Salmonella Typhimurium SL1344의 사람의 트렌스페린(hTf)에 부착된 철 이용에 관한 연구)

  • Choe, Yunjeong;Yoo, Ah Young;Kim, Sam Woong;Hwang, Jihwan;Kang, Ho Young
    • Journal of Life Science
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    • v.27 no.1
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    • pp.72-77
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    • 2017
  • Inorganic iron is essential for various metabolic processes, including RNA synthesis, electron transport, and oxygen detoxification in microorganisms. Many bacterial pathogens compete for iron acquisition in diverse environmental condition such as host. Salmonella Typhimurium SL1344 also requires inorganic iron as a cofactor for growth. When a M9 minimal liquid medium was supplemented with ethylenediamine di-o-hydroxyphenylactic acid (EDDA) which acts as an iron-chelating agent, growth of Salmonella Typhimurium SL1344 in the supplemented medium was completely arrested by deficient of useful iron under iron-depleted condition. However, a number of siderophores, which are small, high-affinity iron chelating compounds secreted by microorganisms such as bacteria and fungi, were produced for utilization of restricted iron under iron-depleted condition. A M9 minimal liquid medium complemented with human transferrin (hTf)-iron complex turned completely off production of siderophores, but growth of Salmonella Typhimurium SL1344 maintained level similar to compare one complemented with iron (III) chloride (FeCl3). This means that human transferrin (hTf)-bound iron can utilize via directly interaction with Salmonella Typhimurium SL1344 without productions of siderophores. Through construction and analysis of negative mutant for utilization of human transferrin (hTf)-bound iron, we confirm that the bacterium can directly use human transferrin (hTf)-bound iron without extracellularly intermediated carriers such as siderophores.

Conservation Treatment of Sand Stone by Pressurized Impregnation with Acrylic Materials (아크릴계 보존처리제를 이용한 사암의 가압함침 보존처리)

  • Kim, Youn-Cheol;Kim, Sa-Duk;Kim, Hyung-Joong
    • Journal of Conservation Science
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    • v.27 no.4
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    • pp.395-401
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    • 2011
  • After pressurized impregnation treatment, which has been proposed as an effective conservation method for stone cultural property, was executed with methyl metacrylate (MMA), MMA-butyl acrylate (PMB73) mixture and MMA-vinyl trimethoxy silane (PMV5) co-monomer mixture, the physical-chemical properties on the sand stone and the granite impregnated were evaluated. Compared to the case of granite, the impregnation ratios of sand stone showed larger values in the range of 3.2 to 3.7 wt% and these were increased up to 32% when the decompression process was applied to autoclave. The physical properties of sand stone such as anti-moisture property, flexural strength, impact property and ultrasonic velocity were also higher values than those of granite, which can be interpreted by high impregnation ratio resulted in many void within sand stone. The impact failure energy was 1.22 J for PMMA, 1.84 J for PMB73, and 2.8 J for PMV5, respectively. Since the inorganic affinity of treatment agent is more effective than the molecular structure of acrylic agent, PMV5 improved inorganic property indicates the optimum impact property.

Solidify Properties of Radioactive Waste using Paraffin Wax (파라핀 왁스를 이용한 방사성 폐기물의 고화 특성)

  • Lee, Han Chul;Chang, Yoon Ho
    • Applied Chemistry for Engineering
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    • v.17 no.4
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    • pp.391-396
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    • 2006
  • When radioactive wastewater was solidified treatment by cement, the drying rate of cement and the volume reduction ratio was decreased because of boric acid component in the wastewater. In order to supplement the demerit, effects of paraffin wax investigated in this study. Paraffin wax has a hydrophobic properties and a low affinity with inorganic materials. When the radioactive wastewater was tested by a small of wax, the compressive strength of solidified waste are decreased Therefore boric acid in radioactive wastewater are first treated by alkali salt and coated by the stearic acid. During the solidification step, The amount of paraffin wax addition get the result that the compressive strength of solidification with cement was the same as that with paraffin wax. The leaching properties of radioactive waste solidified was the same CFL (cumulative fraction leached), PR (penetration rate), effective diffusivity if paraffin wax content in solidified waste was 20% or 25%.

Proteomic Analysis of Fructophilic Properties of Osmotolerant Candida magnoliae

  • Yu, Ji-Hee;Lee, Dae-Hee;Park, Yong-Cheol;Lee, Mi-Gi;Kim, Dae-Ok;Ryu, Yeon-Woo;Seo, Jin-Ho
    • Journal of Microbiology and Biotechnology
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    • v.18 no.2
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    • pp.248-254
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    • 2008
  • Candida magnoliae, an osmotolerant and erythritol producing yeast, prefers D-fructose to D-glucose as carbon sources. For the investigation of the fructophilic characteristics with respect to sugar transportation, a sequential extraction method using various detergents and ultracentrifugation was developed to isolate cellular membrane proteins in C. magnoliae. Immunoblot analysis with the Pma1 antibody and two-dimensional electrophoresis analysis coupled with MS showed that the fraction II was enriched with membrane proteins. Eighteen proteins out of 36 spots were identified as membrane or membrane-associated proteins involved in sugar uptake, stress response, carbon metabolism, and so on. Among them, three proteins were significantly upregulated under the fructose supplying conditions. The hexose transporter was highly homologous to Ght6p in Schizosaccharomyces pombe, which was known as a predominant transporter for the fructose uptake of S. pombe because it exhibited higher affinity to D-fructose than D-glucose. The physicochemical properties of the ATP-binding cassette transporter and inorganic transporter explained their direct or indirect associations with the fructophilic behavior of C. magnoliae. The identification and characterization of membrane proteins involved in sugar uptake might contribute to the elucidation of the selective utilization of fructose to glucose by C. magnoliae at a molecular level.

Quantitative Speciation of Selenium in Human Blood Serum and Urine with AE- RP- and AF-HPLC-ICP/MS

  • Jeong, Ji-Sun;Lee, Jonghae;Pak, Yong-Nam
    • Bulletin of the Korean Chemical Society
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    • v.34 no.12
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    • pp.3817-3824
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    • 2013
  • Various separation modes in HPLC, such as anion exchange (AE), reversed-phase (RP), and affinity (AF) chromatography were examined for the separation of selenium species in human blood serum and urine. While RP- and AE-HPLC were mainly used for the separation of small molecular selenium species, double column AF-HPLC achieved the separation of selenoproteins in blood serum efficiently. Further, the effluent of AF-HPLC was enzymatically hydrolyzed and then analyzed with RP HPLC for selenoamino acid study. The versatility of the hybrid technique makes the in-depth study of selenium species possible. For quantification, post column isotope dilution (ID) with $^{78}Se$ spike was performed. ORC ICP/MS (octapole reaction cell inductively coupled plasma/mass spectrometry) was used with 4 mL $min^{-1}$ Hydrogen as reaction gas. In urine sample, inorganic selenium and SeCys were identified. In blood serum, selenoproteins GPx, SelP and SeAlb were detected and quantified. The concentration for GPx, SelP and SeAlb was $22.8{\pm}3.4\;ng\;g^{-1}$, $45.2{\pm}1.7\;ng\;g^{-1}$, and $16.1{\pm}2.2\;ng\;g^{-1}$, respectively when $^{80}Se/^{78}Se$ was used. The sum of these selenoproteins ($84.1{\pm}4.4\;ng\;g^{-1}$) agrees well with the total selenium concentration measured with the ID method of $87.0{\pm}3.0\;ng\;g^{-1}$. Enzymatic hydrolysis of each selenium proteins revealed that SeCys is the major amino acid for all three proteins and SeMet is contained in SeAlb only.

Enhancement of Electrochemical and Mechanical Properties of 3D Graphene Nanostructures by Dopamine-coating (도파민 코팅을 이용한 3차원 그래핀 나노 구조체의 전기화학적/기계적 특성 향상 연구)

  • Lee, Guk Hwan;Luan, Van Hoang;Han, Jong Hun;Kang, Hyun Wook;Lee, Wonoh
    • Composites Research
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    • v.32 no.6
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    • pp.388-394
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    • 2019
  • Inherited the excellent electrical and mechanical properties based on the low dimensional structure of graphene, three-dimensional graphene nanostructures have gathered great attention as electrochemical energy storage electrodes owing to their high porosity and large specific surface area. Also, having the catecholamine structure, dopamine has been regarded as a multifunctional material to possess high affinity to various organic/inorganic materials and to modify a hydrophobic surface to a hydrophilic one. In this work, through coating dopamine on the three-dimensional graphene nanostructure, we tried to increase the specific capacitance by enhancing the wettability with electrolyte and to improve the mechanical compressive property by strengthening the nano-architecture. As a result, the dopamine-coated nanostructure exhibited significant improvement on the specific capacitance (51.5% increase) and compressive stress (59.6% increase).

Adsorption of Organic Compounds onto Mineral Substrate Prepared from Oyster Shell Waste

  • Jeon, Young-Woong;Jo, Myung-Chan;Noh, Byeong-Il;Shin, Choon-Hwan
    • Environmental Sciences Bulletin of The Korean Environmental Sciences Society
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    • v.10 no.S_2
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    • pp.79-88
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    • 2001
  • Humic acids react with chlorine to produce Trihalomethanes(THMs), known as carcinogens, during disinfection, the last stage in water purification. Currently, the removal of organic humic acids is considered the best approach to solve the problem of THM formation. Accordingly, the current study examined the adsorption of organic compounds of humic acids onto an inorganic carrier prepared from oyster shell waste. The adsorbent used was activated oyster shell powder(HAP) and silver ion-exchanged oyster shell powder(HAP-Ag), with CaCO$_3$ as the control. The adsorbates were phthalic acid, chelidamic acid, catechol, dodecylpyridinium chloride(DP), and 2-ethyl phenol(2-EP). The adsorption experiments were carried out in a batch shaker at $25^{\circ}C$ for 15 hours. The equilibrium concentration of the adsorbate solution was analyzed using a UV spectrophotometer and the data fitted to the Langmuir isotherm model. Since the solution pH values were found to be greater than the pKa values of the organic compounds used as adsorbates, the compounds apparently existed in ionic form. The adsorptive affinities of the organic acid and phenolic compounds varied depending on the interaction of electrostatic forces, ion exchange, and chelation. More carboxylic acids and catechol, rather than DP and 2-EP, were adsorbed onto HAP and HAP-Ag. HAP and HAP-Ag exhibited a greater adsorptive affinity for the organic compounds than CaCO$_3$, used as the control.

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Recent Advances on Ionic Liquid based Mixed Matrix Membrane for CO2 Separation (CO2 분리를 위한 이온성 액체 기반 혼합 매트릭스 멤브레인의 최근 발전)

  • Wang, Chaerim;Patel, Rajkumar
    • Membrane Journal
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    • v.31 no.1
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    • pp.1-15
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    • 2021
  • The membrane-based CO2 capture is a fast-growing branch in gas separating field. Ionic liquid assisted mixed matrix membrane (MMM), which consists of organic fillers with dispersed ionic liquid, shows high potentiality as a candidate for CO2 separation medium. In MMM, various kinds of ionic liquid and inorganic filler are incorporated into polymer to enhance gas separating performance. Especially, the strong interaction between ionic liquid and organic filler gives huge influence on enhancing the separating performance by increasing affinity, selectivity and adsorption of CO2 into the framework. Also the mechanical properties of metal organic framework are positively tuned by input of ionic liquid to improve CO2 permeability and selectivity. In this review, study of various combinations of ionic liquid and metal organic framework (MOF) in the polymeric membrane for carbon dioxide separation is discussed.

Gas Permeation Properties of Carbon Dioxide and Methane for $PEBAX^{TM}$/TEOS Hybrid Membranes ($PEBAX^{TM}$/TEOS 하이브리드 분리막을 통한 이산화탄소와 메탄의 기체투과특성)

  • Kim, Hyunjoon
    • Korean Chemical Engineering Research
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    • v.49 no.4
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    • pp.460-464
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    • 2011
  • Poly(ether-block-amide)(PEBA, $PEBAX^{TM}$) resin is a thermoplastic elastomer combining linear chains of hard-rigid polyamide block interspaced soft-flexible polyether block. It was believed that the hard polyamide block provides the mechanical strength and permeation selectivity, whereas gas transport occurs primarily through the soft polyether block. The objective of this work was to investigate the gas permeation properties of carbon dioxide and methane for $PEBAX^{TM}$-1657 membrane and compare with those obtained for other grade of $PEBAX^{TM}$, $PEBAX^{TM}$-2533. And the organic/inorganic hybrid membranes were prepared using $PEBAX^{TM}$ and TEOS(tetraethoxysilane) by sol-gel process, and gas permeation properties were studied. $PEBAX^{TM}$-2533 membrane exhibited higher gas permeability coefficients than $PEBAX^{TM}$-1657 membrane. This was explained by the increase of chain mobility. The permeability coefficients for $PEBAX^{TM}$/TEOS hybrid membranes were higher than pure $PEBAX^{TM}$ membranes. This results were explained by the reduction of crystallinity of polyamide block by the introduction of TEOS. Ideal separation factor of hybrid membranes does not change much. This might be due to the increase of solubility selectivity.