Chemical vapor deposition method porous membrane preparation

The silica membrane was prepared through sol-gel deposition and chemical vapor deposition methods. The porous a-alumina tube (O.D., 5.0 mm I.D., 3.5 mm length, 300 mm), supplied by Nano Pore Materials Co. Ltd., Korea, was used as a support. The mean pore size and porosity of the support tube were 0.1 pm and 35%, respectively. Tlie effective length of membrane was 100-150 mm at the middle of the tube, and both edges were glazed with a SiO2-BaO-CaO sealant (Nippon Electric Glass, GA-13), and then calcined at 1200°C. 

Some of the methods using more sophisticated equipment for the deposition of Pd or Pd/alloy on porous substrates include, among others [7], the metal-organic chemical vapor deposition (MOCVD) [8, 9], and electron beam evaporation and ion-beam sputtering [10]. On the other hand, electroless plating uses relatively simple equipment. The techniques using sophisticated equipment are quite powerful and especially useful for the deposition of alloy films. However, their major drawbacks are low area of the prepared membranes, difficult for large scale production and/or... 

Barsema JN, Van Der Vegt NFA, Koops GH, Wessling M (2002) Carbon molecular sieve membranes prepared from porous fiber precursor. J Membr Sci 205 (1-2) 239-246 Soffer A, Azariah A, Amar A, Cohen H, Golub D, Saguee S, Tobias H (1997) Method of improving the selectivity of carbon membranes by chemical vapor deposition. US Patent... 

The separation layer, either porous or dense, can be formed using different methods such as sol-gel and template routes, hydrothermal synthesis, chemical vapor deposition (CVD), or physical sputtering, depending on the membrane material and its application. These membrane preparation methods will be described in the following chapters of this book for different membranes and membrane reactors. We note that the preparation of inorganic membranes involves a multi-step high-temperature treatment process. Therefore, inorganic membranes are much more expensive than polymeric ones. 

---