Kenji Sumida, David L. Rogow, Jarad A. Mason, Thomas M. McDonald, Eric D. Bloch, Zoey R. Herm, Tae-Hyun Bae, Jeffrey R. Long

Carbon Dioxide Capture in Metal–Organic Frameworks

Photoinduced reactivity of titanium dioxide

Overview of membrane science and technology membrane transport theory membrane and modules concentration polarization reverse osmosis ultrafiltration microfiltration gas separation pervaporation ion exchange membrane processes - electrodialysis carrier facilitated transport medical applications of membranes other membranes processed.

Membrane Technology and Applications

Conceptions for heat transfer correlation of nanofluids

Generations Yi Ma,† Xiuli Wang,† Yushuai Jia,† Xiaobo Chen,‡ Hongxian Han,*,† and Can Li*,† †State Key Laboratory of Catalysis, Dalian Institute of Chemical Physics, Chinese Academy of Sciences and Dalian National Laboratory for Clean Energy, 457 Zhongshan Road, Dalian 116023, China ‡Department of Chemistry, College of Arts and Sciences, University of Missouri-Kansas City, 5100 Rockhill Road, Kansas City, Missouri 64110, United States

Titanium dioxide-based nanomaterials for photocatalytic fuel generations.

A porous α-alumina support tube, polished with a finely powdered X-type zeolite for use as seeds, was placed vertically in an autoclave containing an aqueous mixture of water glass and sodium aluminate. Hydrothermal synthesis was carried out at 90 °C for 24 h. A polycrystalline layer of Y-type zeolite was thus formed on the outer surface of the support tube. After washing and drying in air, permeances of single components and mixtures of CO2 and N2, as well as CH4, C2H6, and SF6, were determined. The CO2 permeance was higher than that of N2 at temperatures of 30−130 °C. When an equimolar mixture of CO2 and N2 was fed into the feed side, the CO2 permeance was nearly equal to that for the single-component system and the N2 permeance for the mixture was greatly decreased, especially at lower permeation temperatures. This was due to selective adsorption of CO2 in subnanometer micropores of the membrane. At 30 °C, the permeance of CO2 was higher than 10-7 mol·m-2·s-1·Pa-1, and the permselectivity of CO2 to N2 ...

Formation of a Y-Type Zeolite Membrane on a Porous α-Alumina Tube for Gas Separation

NANOPHASE materials, characterized by an ultrafine grain size, have stimulated much interest in recent years1–11 by virtue of their unusual mechanical, electrical, optical and magnetic properties. Nanophase ceramics are of particular interest because they are more ductile at elevated temperatures than are coarse-grained ceramics11—an important property for the fabrication of ceramic components. Preparing materials that are both dense and fine-grained, however, has proved difficult: the high sintering temperatures generally required to obtain high densities can also lead to exaggerated grain growth, resulting in coarse-grained, nonuni-form materials. Sintering at lower temperatures gives a much finer grain size, but does not in general result in high-density materials. We show here that dense nanostructured titania, with density >99% of the theoretical maximum and an average grain size of less than 60 nm, can be prepared by sintering a titanium oxide sol gel near the anatase–rutile phase transformation temperature (about 600 °C). The increased mobility of the atoms during the phase transformation enhances the sintering rate at lower temperatures, suggesting that this method could be used more generally to produce nanophase materials with near theoretical densities.

Densification of nanostructured titania assisted by a phase transformation

A thin palladium membrane was formed inside the porous wall of an [alpha]-alumina support tube of 2.0-mm i.d. and 2.6-mm o.d. by a metal-organic chemical vapor deposition (MOCVD) process in which the reaction temperature was continuously increased. The metal source, palladium(II) acetate, was decomposed in argon under reduced pressure. For a membrane prepared with a maximum CVD temperature of 300 C, the hydrogen permeance and the selectivity to nitrogen in the range of 300--500 C were respectively higher than 0.1 mol/(m[sup 2][center dot]s) and 1,000 when the hydrogen pressure in the upstream side was about 0.1 MPa. Repeated temperature changes between 100 and 300 C revealed that the membrane was resistant to hydrogen embrittlement.

Thin Palladium Membrane Formed in Support Pores by Metal-Organic Chemical Vapor Deposition Method and Application to Hydrogen Separation

Separation of carbon dioxide from nitrogen using ion-exchanged faujasite-type zeolite membranes formed on porous support tubes

Rate process concerning the formation of TiO2 fine crystalline particles by the gas-phase reaction of TiCl4 and O2 are studied using aerosol reactors. Chemical reaction of TiCl4, sintering of particles, mixing of reactants, and transformation from anatase to rutile are evaluated as the system parameters of the simulation model proposed. The crystallite size in the range of 55–65 nm at 1,273 K is predicted well by a model that assumes the maximum fusible particle size, 15 nm in this case.

The defect concentration in the TiO2 crystallites strongly affects the transformation rate, and anatase particles produced at 1,173 K are transformed to rutile more rapidly than those produced at 1,373 K. The transformation is simulated quantitatively by the model with the coordinates for elapsed time, particle size and rutile fraction. The model can be applied to such particle production processes as collision, sintering and crystal transformation occurring simultaneously.

Shigeharu Morooka

Papers

Formation of a Y-Type Zeolite Membrane on a Porous α-Alumina Tube for Gas Separation

Densification of nanostructured titania assisted by a phase transformation

Thin Palladium Membrane Formed in Support Pores by Metal-Organic Chemical Vapor Deposition Method and Application to Hydrogen Separation

Separation of carbon dioxide from nitrogen using ion-exchanged faujasite-type zeolite membranes formed on porous support tubes

Growth and transformation of TiO2 crystallites in aerosol reactor