Ceramic membranes preparation

Xomeritakis G. and Lin Y.S., Chemical vapor deposition of solid oxides in porous media for ceramic membrane preparation. Comparison of experimental results with semianalytical solutions, Ind. Eng. Chem. Res, 55 2607 (1994). 

R.S.A. de Lange, J.H.A. Hekkink, K. Keizer and A.J. Burggraaf, Formation and characterisation of supported microporous ceramic membranes prepared by sol-gel modification techniques. /. Membr. Sci., 99 (1995) 57-75. 

III. BASIC PRINCIPLES IN POROUS CERAMIC MEMBRANE PREPARATION... 

Vercauteren S, Keizer K, Vansant EF, Luyten J, Leysen R. Porous ceramic membranes preparation, transport properties and applications. J Porous Mater. 1998 5 241-58. 

Xu, Q., and Anderson, M. (3994). Sol-gel route to synthesis of microporous ceramic membranes preparation and characterization of microporous TiOz and ZrOz xerogels. J Am. Ceram. Soc. 77 f939-f943. 

Figure 4.7 SEM images of a composite Pd-ceramic membrane prepared by the electroless plating method (a) cross-section (b) palladium surface. Reproduced from [16]. With permission from Elsevier.

The thickness of porous ceramic membranes prepared in this manner is typically in the range of a few millimetres (Larbot, 1996), although thinner membranes have been realised (Sahibzada e/a/., 2000).Tape casting is a high volume production technique for fiat sheet membranes and is employed on both a research and commercial scale. 

Slip casting method for ceramic membrane preparation. 

De Lange, R. S. A., Hekkink, J. H. A., Keizer, K. and Burggraaf, A. J. (1995a) Formation and characterization of supported microporous ceramic membranes prepared by sol-gel modification techniques. Journal of Membrane Science, 99,57-75. 

In this case study, a zirconia-alumina membrane has been developed using the sol-gel technique with and without support.6-7 The porous ceramic was prepared to fabricate the membrane support. A thin film of aluminum and zirconium were formed on the porous ceramic support. Unsupported membrane was also prepared. The unsupported membrane was not strong enough to hold a high-pressure gradient it was very fragile and not useful... 

Fig. 4. Configuration of a ceramic membrane reactor for partial oxidation of methane. The membrane tube, with an outside diameter of about 6.5 mm and a length of up to about 30 cm and a wall thickness of 0.25-1.20 mm, was prepared from an electronic/ionic conductor powder (Sr-Fe-Co-O) by a plastic extrusion technique. The quartz reactor supports the ceramic membrane tube through hot Pyrex seals. A Rh-containing reforming catalyst was located adjacent to the tube (57).

Fig. 6. Configuration of a ceramic membrane reactor for partial oxidation of methane. The membrane disk was prepared by pressing Bao.5Sro.5Coo.8Feo.2O3-s oxide powder in a stainless steel module (17 mm inside diameter) under a pressure of (1.3-1.9) X 109 Pa. The effective area of the membrane disk exposed to the feed gas (CH4) was 1.0 cm2 (72).

Larbot, A., J. A. Alary, C. Guizard, L. Cot and J. Gillot. 1987. New inorganic ultrafiltration membranes Preparation and characterization. Int. J. High Technology Ceramics 3 145-51. 

Terpstra, R. A., B. C. Bonekamp and H. J. Veringa. 1988. Preparation, characterization and some properties of tubular alpha alumina ceramic membranes for microfiltration and as a support for ultrafiltration and gas separation membranes. Desalination 70 395-404. 

Hollow glass microbeads Porous ceramic membranes Microbeads coated by Ti02 particles Porous ceramic Ti02 and ZnO membranes prepared by sol-gel technique... 

While considerable progress has been made in the preparation of ceramic membranes by sol-gel processing, the development of membranes from hybrid polymers is in its infancy (see also Section V). This is, nevertheless, a very promising area of development, because the possibility of forming mechanically stable membranes by inorganic polycondensation is implemented by the possibility to incorporate organic functions. 

In this chapter membrane preparation techniques are organized by membrane structure isotropic membranes, anisotropic membranes, ceramic and metal membranes, and liquid membranes. Isotropic membranes have a uniform composition and structure throughout such membranes can be porous or dense. Anisotropic (or asymmetric) membranes, on the other hand, consist of a number of layers each with different structures and permeabilities. A typical anisotropic membrane has a relatively dense, thin surface layer supported on an open, much thicker micro-porous substrate. The surface layer performs the separation and is the principal barrier to flow through the membrane. The open support layer provides mechanical strength. Ceramic and metal membranes can be either isotropic or anisotropic. 

During the last few years, ceramic- and zeolite-based membranes have begun to be used for a few commercial separations. These membranes are all multilayer composite structures formed by coating a thin selective ceramic or zeolite layer onto a microporous ceramic support. Ceramic membranes are prepared by the sol-gel technique described in Chapter 3 zeolite membranes are prepared by direct crystallization, in which the thin zeolite layer is crystallized at high pressure and temperature directly onto the microporous support [24,25],... 

The mechanical properties of the membrane are essential in operation and module design. For instance, hollow carbon fibers fabricated by pyrolysis of polymers are seemingly too brittle for practical applications [111]. Ceramic capillaries prepared by extrusion are much stronger, but appear limited in maximum length due to... 

---