Micro-porous glass membranes

In the present study, our interest is focused on a membrane reactor in which the membrane can be employed as a large pore catalyst for the convection flow of reactants. Propylene epoxidation to produce propylene oxide (PO) is taken as a model reaction of parallel-consecutive reactions by using a Re-Ag immobilized in the pores of a micro-porous-glass membrane (MPG). The objectives of this paper are to clarify (1) the reaction kinetics in partial and total oxidation differing from the packed bed reactors,... 

In the last years increasing research activities in the fields of membrane science [1, 2], chemical sensors [3], confined matter [4] and micro-reaction engineering [5] have evoked a new interest on porous glass membranes. Furthermore, such membranes are ideal model systems for the investigation of transport processes in porous structures. This broad spectrum of applications demands variable texture properties. 

The optical transparency of the porous glass membranes is interesting for sensor applications. It depends on the structural features of the membranes [13]. The UV-VIS spectra of micro- and mesoporous glass membranes are compared in Fig. 6. The membranes with an... 

T. Nakashima, M. Shimizu, M. Kuldzaki, Membrane emulsification hy micro-porous glass, Key Eng. Mater. 1991, 61/62, 513. 

The membrane (Micro Porous Glass=MPG, Ise Industry Production Si02 70-80, AI2O3 4-6, BO3 10-12 wt.%) used in this study was 10 mm OD, 8 mm ID and 50 mm length with the pore diameter of 0.34 micron meters. For the immobilization of the catalyst in the membrane pores, Ag and Re were separately supported. A silver ketenide was formed in the membrane pores by the reaction of the two solutions, a mixed solution of acetic anhydride (3.0 g) and pyridine (50 cm ), at room temperature for 12 hr... 

Porous glass membranes (PGMs) are used for many applications, especially in membrane separation processes such as micro- and ultra-filtration,gas separation, demulsification medium and membrane emulsification, gas-liquid contacting process and gas dispersion process. ... 

The use of Schott s porous glass membremes (pore sizes from 10 to 90 nm) in the separation of proteins with molecular weights from 14,400 to 450,000 is illustrated by Langer and Schnabel [85] who show a decrease in retention with increasing pore size for different proteins. Due to the chemical nature of the membrane material, it lends itself to surface modifications, including the coupling of enzymes or the attachment of micro-organisms. 

The Tohoky University, Japan (Min et al.) reported a p-PEFC using micro-fabrication techniques [3]. This FC is based on two different designs, the alternatively inverted structure and the coplanar structure . These structures use Si substrates with porous SiOj layers with Pt-based catalytic electrodes and gas feed holes, glass substrates with micro-gas channels and a polymer membrane (Flemion S). In spite of a reported enhancement [4], the FC reached poor results, the power density is only 0.8 mW cm . ... 

Both acid anodized aluminum (alumite membrane) (141, 142) and nuclear track-etched membranes have been used as a template. The nuclear track-etched membranes are prepared by irradiation/chemical etching (143) and contain linear, cylindrical pores of nearly uniform pore diameter. This ensures that the holes in the template are circular and approximately of the same diameter. More recently, porous nano-channel glass (144), and etched wafers of micro-channel plate glass have served as templates (125). The advantage of using porous membranes as templates can be found in their function as arrays of microelectrodes. They exhibit small potential drops, which make the electrochemical measurements possible when... 

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