Fine continuous oxide fibers

The last quarter of the twentieth century saw tremendous advances in the processing of continuous, fine diameter ceramic fibers. Figure 6.4 provides a summary of some of the important synthetic ceramic fibers that are available commercially. We have included in Fig. 6.4 two elemental fibers, carbon and boron, while we have excluded the amorphous, silica-based glasses. Two main categories of synthetic ceramic fibers are oxide and nonoxides. A prime example of oxide fibers is alumina while that of nonoxide fibers is silicon carbide. An important subclass of oxide fibers are silica-based glass fibers and we devote a separate chapter to them because of their commercial importance (see chapter 7). There are also some borderline ceramic fibers such as the elemental boron and carbon fibers. Boron fiber is described in this chapter while carbon fiber is described separately, because of its commercial importance, in Chapter 8. 

Hollow-fiber MBR have also been used for the production of a number of other fine chemicals. Molinari et al [4.42] used such a MBR for the production of isovaleraldehyde from isoamyl alcohol using Gluconobacter oxidans. In their work hydrophobic hollow-fiber membranes were used in order to continuously extract the aldehyde, thus, avoiding its oxidation to the corresponding acid. Hollow-fiber MBR have also been used by Ko-yama et al [4.27] in the synthesis of L-aspartic acid by E. coli, and by Cantarella et al... 

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