Metal-dispersed alumina membranes

M. Chai, M. Machida, K. Eguchi and H. Arai, Promotion of Hydrogen Permeation on Metal-Dispersed Alumina Membranes and its Application to a Membrane Reactor for Methane Steam Reforming , Appl. Catal. A, 110 239-50 (1994). 

Chai M., Machida M., Eguchi K. and Arai H., Promotion of hydrogen permeation on metal-dispersed alumina membranes and its application to a membrane reactor for methane steam reforming, Appl. Catal. A 110 239 (1994). 

K. Eguchi, H. Arai, Preparation and characterization of metal-dispersed alumina membranes for selective separation of hydrogen, J. Membr. Set. 1994,... 

Lu et al7 applied the vacuum filtration fabrication to the comparison of films of as-purified SWNTs and separated metallic SWNTs (approximately 85% purity in metallicity). In the fabrication, the two nanotube samples were each dispersed into an aqueous solution of SDS. A porous alumina membrane was used as filter in the vacuum filtration of the suspended SWNTs. After filtration, the film on the filter was washed repeatedly with deionized water to remove the surfactant SDS, for which the progress in surfactant removal via... 

In a collaborative work with Schmid et al., the filling of nanoporous alumina membranes of various pore widths was carried out in two different ways from the decomposition of [Ru(COD)(COT)] in THF/MeOH mixtures in the absence of stabilizer [128]. The first approach involved the impregnation of alumina support with colloidal solutions of RuNPs of different sizes which were dependent on the ratio of MeOH/THF in the reaction mixture. Colloidal solutions were transferred into membranes by vacuum induction. Only a few agglomerates were observed outside of the pores whereas dense areas were located within the membrane channels. The second approach consisted of the room-temperature decomposition of [Ru(COD)(COT)] under 3 bar of Ha following the deposition of this metal precursor inside the pores. In this way, homogeneous materials displaying well-dispersed RuNPs were obtained in the pores of alumina membranes. The size of the particles depended on the pore diameter of the template. These materials were evaluated in two catalytic reactions, i.e. the hydrogenation of 1,3-butadiene and... 

Up to now, a variety of non-zeolite/polymer mixed-matrix membranes have been developed comprising either nonporous or porous non-zeolitic materials as the dispersed phase in the continuous polymer phase. For example, non-porous and porous silica nanoparticles, alumina, activated carbon, poly(ethylene glycol) impregnated activated carbon, carbon molecular sieves, Ti02 nanoparticles, layered materials, metal-organic frameworks and mesoporous molecular sieves have been studied as the dispersed non-zeolitic materials in the mixed-matrix membranes in the literature [23-35]. This chapter does not focus on these non-zeoUte/polymer mixed-matrix membranes. Instead we describe recent progress in molecular sieve/ polymer mixed-matrix membranes, as much of the research conducted to date on mixed-matrix membranes has focused on the combination of a dispersed zeolite phase with an easily processed continuous polymer matrix. The molecular sieve/ polymer mixed-matrix membranes covered in this chapter include zeolite/polymer and non-zeolitic molecular sieve/polymer mixed-matrix membranes, such as alu-minophosphate molecular sieve (AlPO)/polymer and silicoaluminophosphate molecular sieve (SAPO)/polymer mixed-matrix membranes. 

The chemical composihons of the zeolites such as Si/Al ratio and the type of cation can significantly affect the performance of the zeolite/polymer mixed-matrix membranes. MiUer and coworkers discovered that low silica-to-alumina molar ratio non-zeolitic smaU-pore molecular sieves could be properly dispersed within a continuous polymer phase to form a mixed-matrix membrane without defects. The resulting mixed-matrix membranes exhibited more than 10% increase in selectivity relative to the corresponding pure polymer membranes for CO2/CH4, O2/N2 and CO2/N2 separations [48]. Recently, Li and coworkers proposed a new ion exchange treatment approach to change the physical and chemical adsorption properties of the penetrants in the zeolites that are used as the dispersed phase in the mixed-matrix membranes [56]. It was demonstrated that mixed-matrix membranes prepared from the AgA or CuA zeolite and polyethersulfone showed increased CO2/CH4 selectivity compared to the neat polyethersulfone membrane. They proposed that the selectivity enhancement is due to the reversible reaction between CO2 and the noble metal ions in zeolite A and the formation of a 7i-bonded complex. 

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