• Title/Summary/Keyword: membrane chemistry

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Effect of Electrolyte on Preperation of Porous Alumina Membrane by Anodic Oxidation (양극산화에 의한 다공성 알루미나 막의 제조시 전해질의 영향)

  • Lee, Chang-Woo;Hahm, Yeong-Min;Kang, Hyun-Seop;Chang, Yoon-Ho
    • Applied Chemistry for Engineering
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    • v.9 no.7
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    • pp.1047-1052
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    • 1998
  • The porous alumina membrane was prepared from aluminum metal(99.8%) by anodic oxidation using DC power supply of constant current mode in aqueous solution of sulfuric, oxalic, phosphoric and chromic acid. Pore size and distribution, membrane thickness, morphology and crystal structure were examined with several anodizing conditions : reaction temperature, electrolyte concentration, current density and electrolyte type. It was found that ultrafiltration membrane was fabricated in electrolyte of sulfuric, and oxalic acid. On the other hand, microfiltration membrane was fabricated in electrolyte of phosphoric, and chromic acid. Also, it was shown that crystal structure of porous alumina membrane prepared in sulfuric, oxalic, and phosphoric acid was amorphous, whereas porous alumina membrane prepared in chromic acid had ${\gamma}$ type of crystal structure.

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Performance Analysis of Water Gas Shift Reaction in a Membrane Reactor (막반응기에서의 수성가스전이반응의 성능 분석)

  • Lim, Hankwon
    • Applied Chemistry for Engineering
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    • v.25 no.2
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    • pp.204-208
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    • 2014
  • This study investigated the effect of hydrogen permeance and selectivity, catalyst amount, $H_2O/CO$ ratio in a feed stream, and Ar sweep gas on the performance of a water gas shift reaction in a membrane reactor. It was observed that a minimum hydrogen selectivity of 100 was needed in a membrane reactor to obtain a hydrogen yield higher than the one at equilibrium and the hydrogen yield enhancement gradually decreased as the hydrogen permeance increased. The CO conversion in a membrane reactor initially increased with the catalyst amount and reached a plateau later for a membrane reactor with a low hydrogen permeance while the high CO conversion independent of a catalyst amount was observed for a membrane reactor with a high hydrogen permeance. For the $H_2O/CO$ ratio in a feed stream higher than 1.5, a hydrogen permeance had little effect on the CO conversion in a membrane reactor and it was found that a minimum Ar molar flow rate of $6.7{\times}10^{-6}mol\;s^{-1}$ was needed to achieve the CO conversion higher than the one at equilibrium in a membrane reactor.

Biochemical Aspect of Superoxide Toxicity to Plant Mitochondria (식물 미토콘드리아에 대한 Superoxide독성의 생화학적 측면)

  • Jung, Jin;In, Man-Jin
    • Applied Biological Chemistry
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    • v.32 no.1
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    • pp.23-29
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    • 1989
  • Biochemical consequence of the accumulation in cells of superoxide $(O^{-}_{2})$ which was proposed to be probably a common chemical factor in the secondary process of the mechanism of chilling injury as well as in the visible light photodamage in cells of higher plants, has been investigated in the present work. Especially focused was the destructive effect of $O^{-}_{2}$ on the biochemical activity of mitochondria, as informations which support the suggestion that mitochondrial inner membrane is the major site of $O^{-}_{2}$ production have been collected. Mitochondria and submitochondrial particles (SMP) were prepared from soybean hypocotyls for this case study. When SMP were treated with the electrolytically produced $O^{-}_{2}$ they suffered not only inhibition of the membrane-bound enzymes as demonstrated by cytochrome c oxidase, but also lipid peroxidation of membrane as proved by malondialdehyde production. Malate dehydrogenase present in the protein extract from mitochondrial matrix was also inhibited by the $O^{-}_{2}$ treatment. These results exhibited the chaotic effect of the overproduction and accumulation of $O^{-}_{2}$ in cells under a certain abnormal circumstance such as environmental stress on the physiological function of mitochondrial; disruption of the cellular metabolic pathways and the structural integrity of membrane.

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Determination of Salicylate by Selective Poly(vinylchloride) Membrane Electrode Based on N,N'-1,4-Butylene Bis(3-methyl salicylidene iminato) Copper(II)

  • Mazloum Ardakani, M.;Jamshidpoor, M.;Naeimi, H.;Heidarnezhad, A.
    • Bulletin of the Korean Chemical Society
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    • v.27 no.8
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    • pp.1127-1132
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    • 2006
  • A new salicylate-selective electrode based on the complex N,N'-1,4-butylene bis(3-methyl salicylidene iminato) copper(II) as the membrane carrier was developed. The electrode exhibits a good Nernstian slope of 59.1 ${\pm}$ 1.0 mV/decade and a linear range of $1.0\;{\times}\;10^{-6}$-1.0 M for salicylate. The limit of detection was $5.0\;{\times}\;10^{-7}$ M. It has a fast response time 10 s and can be used for more than three months. The selective coefficients were determined by the fixed interference method (FIM) and could be used in the pH range 4.5-10.5. It was employed as an indicator electrode for direct determination of salicylate in pharmaceutical samples.

Titanium Acetylacetonate as an Excellent Ion-Carrier in Construction of Iodide Sensor

  • Ganjali, Mohammad Reza;Daftari, Azadeh;Mizani, Farhang;Salavati-Niasari, Masoud
    • Bulletin of the Korean Chemical Society
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    • v.24 no.1
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    • pp.23-26
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    • 2003
  • Titanium acetylacetonate was used in the construction of a PVC-based membrane electrode. This sensor shows very good selectivity for iodide ion over a wide variety of common inorganic and organic anions. It exhibits Nernstian behavior with a slope of 59.1 mV per decade. The working concentration ranges of the sensor are with a detection limit of $3.0\;{\times}\;10^{-6}\;M$. The response time of the sensor is very fast (<8 s), and can be used for at least twelve weeks in the pH range of 4.0-9.2. The best performance was obtained with a membrane composition of 30% PVC, 65% dibutylphthalate, 3% titanium acetylacetonate and 2% hexadecyltrimethylammonium bromide. The proposed sensor was successfully applied as an indicator electrode for titration of iodide with silver ion.