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Volume 23 (1998)
- Issue 6 Pages 280-
- Issue 5 Pages 226-
- Issue 4 Pages 156-
- Issue 3 Pages 104-
- Issue 2 Pages 50-
- Issue 1 Pages 2-
Volume 23, Issue 2
Displaying 1-7 of 7 articles from this issue
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Katsuki Kusakabe, Shigeharu Morooka1998 Volume 23 Issue 2 Pages 50-54
Published: March 01, 1998
Released on J-STAGE: March 04, 2011
JOURNAL FREE ACCESSThis article reviews recent research works on inorganic membranes for gas separation. Porous silica membranes with H2/N2 selectivities higher than 1, 000 have been produced by chemical vapor deposition and sol-gel methods and applied to membrane reactors and hydrogen recovery processes at elevated temperatures. Carbon membranes developed recently show high 02/N2 selectivities at high permeation rates. Oxygen ion-conductive dense membranes as well as CO2-selective porous membranes have been also realized. The high permeation of CO2 through Y-type zeolite membranes is explained in terms of surface diffusion which is sensitive to pore dimensions.View full abstractDownload PDF (697K) -
Masahiko Matsukata1998 Volume 23 Issue 2 Pages 55-61
Published: March 01, 1998
Released on J-STAGE: March 04, 2011
JOURNAL FREE ACCESSState-of-the art of hydrocarbon separation technology by inorganic membranes is reviewed. Targets for hydrocarbon separation are classified into five groups : H2/Lower hydrocarbons, alkane/alkene, straight chain hydrocarbons/branched hydrocarbons, aliphatic hydrocarbons/aromatic hydrocarbons, and aromatic hydrocarbon mixtures. Various types of microporous inorganic membranes, amorphous silica, zeolites and carbon membranes, have been under development. Some of them show very high permselectivities, indicating the promising prospects of inorganic membrane technology. While molecular sieving property has long been anticipated to appear on the basis of size recognition by micropores smaller than 1 nm, there have been a few reports with conclusive evidence on the separation by molecular sieving. On the other hand, the difference in adsorption properties into a membrane can lead to the appearance of permselectivity particularly at lower temperatures.View full abstractDownload PDF (852K) -
Hidetoshi Kita1998 Volume 23 Issue 2 Pages 62-69
Published: March 01, 1998
Released on J-STAGE: March 04, 2011
JOURNAL FREE ACCESSInorganic membrane is a promising candidate for a pervaporation membrane because of their high thermal stability and high chemical resistance. Recently high pervaporation performances of microporous silica and zeolite membranes have been reported and A type zeolite membrane module hasbeen put to practical use for dehydration of organic liquids. Progress in the application of inorganic molecular sieve membranes for pervaporation is reviewed.View full abstractDownload PDF (902K) -
Toshinori Tsuru1998 Volume 23 Issue 2 Pages 70-79
Published: March 01, 1998
Released on J-STAGE: March 04, 2011
JOURNAL FREE ACCESSNanofiltration by porous inorganic membranes is reviewed from the viewpoint of preparation methods as well as the applications. Sol-gel methods have been widely applied to fabricate porous inorganic membranes, and alumina, titania, zirconia and silica-zirconia have been successfully applied to fabricate inorganic membranes having nanofiltration performance.
Summarized are also other preparation techniques including pyrolysis of polymeric membranes, organic/inorganic hybrid membranes, hydrothermal method for zeolite membranes, anodic oxidation, dynamic membranes, clay membranes. Applications of inorganic membranes reviewed are categorized into separation of electrolytes, nanofiltration of organic solutions, electro-ultrafiltration and membrane reactor application.View full abstractDownload PDF (1322K) -
Shin-ichi Furukawa, Tomoshige Nitta1998 Volume 23 Issue 2 Pages 80-86
Published: March 01, 1998
Released on J-STAGE: March 04, 2011
JOURNAL FREE ACCESSUnderstanding the permeation phenomena through molecular interactions and membrane structures is important for effective membrane design. This paper describes a brief review of a novel non-equi-librium molecular dynamics (μVT-NEMD) technique, which we have recently applied for simulating gas permeation, and some results calculated for permeation of single and mixed gases through carbon membranes with slit-shaped pores. One important observation obtained from simulations may be an image of surface flow for permeating gases. It is also noted that permselectivity of mixed gases has been controlled by the competitive adsorption equilibrium at the feed side of membrane when calculations were performed under the assumption of local adsorption equilibrium between the feed gas and the entrance part of a pore. A small heterogeneity on pore surfaces is found to result in large decrease in the permeation fluxes. Simulations on gas permeation at the feed side provide a view that molecules enter into the slit-pore either directly into the pore mouth or indirectly through the outer surface of the pore after they are adsorbed. Frequent moves of molecules onto the outer surface from the pore inside are also observed when molecules leave the pore to the gas phase.View full abstractDownload PDF (1034K) -
Yutaka Matsumoto, Yoshio Okada, Masao Sudoh, Yoshimi Suzuki1998 Volume 23 Issue 2 Pages 87-94
Published: March 01, 1998
Released on J-STAGE: March 04, 2011
JOURNAL FREE ACCESSProperties of protein solutes adsorbed on ceramic membrane by using a quartz-crystal microbalance (QCM) were evaluated in situ. This frequency of piezoelectric AT-cut quartz resonator changed according to the amount of solute adsorbed on the quartz-crystal surface. Ceramic thin membrane, which was mainly titanium oxide (TiO2), was coated on the QCM surface using sol-gel method. An adsorption behavior of bovine serum albumin (BSA) on the TiO2-QCM was investigated.
The amount of BSA adsorption increased with increasing BSA concentration, and reached a maximum value near the isoelectric point of BSA solution. The cohesion force acting among BSA molecules was considered to become strongest because the electrostatic repulsion force was weakened, and then the BSA molecules were accumulated by adsorption onto the membrane surface. A higher ionic strength gave a lower BSA adsorption at a pH near the isoelectric point. The pH at maximum adsorption of BSA in a high ionic strength shifted to a more acidic pH than that in a low ionic strength. The adsorption amount of BSA increased by hydrophobilization of TiO2 surface. The equilibrium amount of BSA adsorbed at pH4.8 could be expressed by a Freundlich type's adsorption isotherm.View full abstractDownload PDF (1079K) -
Masakazu Kondo, Yasuo Matuo, Yosio Morigami, Jun Abe1998 Volume 23 Issue 2 Pages 95-99
Published: March 01, 1998
Released on J-STAGE: March 04, 2011
JOURNAL FREE ACCESSZeolite NaA membrane was prepared on the surface of porous tubular support composed of mullite, α-alumina and cristobalite using the hydrothermal synthesis. Based on pervaporation and vapor permeation measurements using H2O/EtOH, zeolite NaA membrane showed very high water-selective permeation irrespective of the ethanol concentration. The tubular-type modules have been fabricated with zeolite membrane, which has excellent mechanical strength, thermal resistance and extreamly high durability to solvents.
The preparation procedure is briefly mentioned and the characteristics of the zeolite NaA membrane are shown with some experimental results.View full abstractDownload PDF (911K)
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