• Title/Summary/Keyword: membrane chemistry

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Separation of Hydrogen-Nitrogen Gas Mixture by PTMSP-Silica-PEI Composite Membranes

  • Lee, Hyun-Kyung;Kang, Tae-Beom
    • Proceedings of the Membrane Society of Korea Conference
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    • 2004.05a
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    • pp.144-147
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    • 2004
  • Organosilicon polymers have long paid attention as functional polymers [1,2]. Among others, poly- (1-trimethylsilyl-1-propyne) [PTMSP] is a polymer, which forms a gas separating membrane with extraordinary high gas permeability. In particular, composite membranes that constituted two different matrices (inorganic and organic) have been recently developed in order to improve the permeation characteristics.(omitted)

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Improving the smoking quality of papermaking tobacco sheet extract by using electrodialysis

  • Zhang, Zenghui;Ge, Shaolin;Jiang, Chenxiao;Zhao, Yue;Wang, Yaoming
    • Membrane and Water Treatment
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    • v.5 no.1
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    • pp.31-40
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    • 2014
  • Papermaking tobacco sheet is an important reclaimed process for cigarette making. Traditionally, the pressure driven membrane was often used to isolate the effective compounds from the tobacco sheet extract. However, this method is difficult to remove small ionic compounds. Besides, membrane fouling is a major problem for effective use of these pressure driven membrane technologies. In this study, the electrodialysis process is used to removal the chloride ions and nitrate ions, thus the smoking quality of papermaking tobacco sheet extract can get improved. Three types of electrolytes ($Na_2SO_4$, NaCl and HCl) are chosen to prevent the generation of precipitation. The results indicate that 0.1mol/L HCl at current density of $30mA/cm^2$ is the optimal condition for the electrodialysis process. The removal rates of the Cland $NO{_3}^-$ in tobacco sheet extract are 97% and 98.4%, respectively. The electrodialysis process cost was estimated to be 0.11$/L. Naturally, electrodialysis is not only technological feasible, environmental-friendly and economical-attractive for tobacco extract treatment.

High-yield Expression and Characterization of Syndecan-4 Extracellular, Transmembrane and Cytoplasmic Domains

  • Choi, Sung-Sub;Kim, Ji-Sun;Song, Jooyoung;Kim, Yongae
    • Bulletin of the Korean Chemical Society
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    • v.34 no.4
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    • pp.1120-1126
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    • 2013
  • The syndecan family consists of four transmembrane heparan sulfate proteoglycans present in most cell types and each syndecan shares a common structure containing a heparan sulfate modified extracellular domain, a single transmembrane domain and a C-terminal cytoplasmic domain. To get a better understanding of the mechanism and function of syndecan-4 which is one of the syndecan family, it is crucial to investigate its three-dimensional structure. Unfortunately, it is difficult to prepare the peptide because it is membrane-bound protein that transverses the lipid bilayer of the cell membrane. Here, we optimize the expression, purification, and characterization of transmembrane, cytoplasmic and short extracellular domains of syndecan4 (syndecan-4 eTC). Syndecan-4 eTC was successfully obtained with high purity and yield from the M9 medium. The structural information of syndecan-4 eTC was investigated by MALDI-TOF mass (MS) spectrometry, circular dichroism (CD) spectroscopy, and nuclear magnetic resonance (NMR) spectroscopy. It was confirmed that syndecan-4 eTC had an ${\alpha}$-helical multimeric structure like transmembrane domain of syndecan-4 (syndecan-4 TM) in membrane environments.

Lead-Selective Poly(vinyl chloride) Membrane Electrode Based on 1-Phenyl-2-(2-quinolyl)-1,2-dioxo-2-(4-bromo) phenylhydrazone

  • Zare, Hamid Reza;Ardakani, Mahammad Mazloum;Nasirizadeh, Navid;Safari, Javad
    • Bulletin of the Korean Chemical Society
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    • v.26 no.1
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    • pp.51-56
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    • 2005
  • A PVC membrane electrode for lead ion based on 1-phenyl-2-(2-quinolyl)-1,2-dioxo-2-(4-bromo) phenylhydrazone (PQDBP) as ionophore was demonstrated. The optimum composition of the membrane was 30 wt% poly(vinyl chloride), 60 wt% dibutyl phthalate as a plasticizer, 4 wt% ionophore and 6 wt% sodium tetraphenylborate as additive. The electrode exhibits a Nernstian response (28.7 mV decade$^{-1}$) for Pb$^{2+}$ over a wide concentration range (1.0 ${\times}$ 10$^{-1}$ to 1 ${\times}$ 10$^{-6}$ M) with a detection limit of 6.0 ${\times}$ 10$^{-7}$ M. This sensor has a short response time and can be used for at least 2 months without any divergence in potentials. The proposed electrode could be used in a pH range of 3.0-6.0 and revealed good selectivities for Pb$^{+2}$ over a wide variety of other metal ions. It was successfully applied as an indicator electrode for the potentiometric titration of lead ion with potassium chromate and for the direct determination of lead in mine.