Titania microporous layers

The preparation of the required microporous ceramic layers is possible by the sol-gel route from stable colloidal dispersions with individual nanoparticles of less than 10 nm. Different types of ceramic nanofilters have been prepared from such aqueous or organic sols of the following oxides y-alumina, zirconia, ° hafnia," and titania. ... 

This ligand then acts as a functionality locker when substoichiometric hydrolysis ratios are used. A ratio acacH/M greater than 1 prevents precipitation and leads to stable colloids or gels. Consequently, with a good formulation choice, sols can be prepared in air without precipitation. Either titania or zirconia ultrafiltration layers have been used as supports for these membranes. Figure 17 is a cross-sectional image of a zirconia microporous membrane that is 0.2 jum thick. 

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