Tech Briefs

Photocatalytic Coats in Glass Drinking-Water Bottles

According to a proposal, the insides of glass bottles used to store drinking water would be coated with films consisting of or containing TiO2. In the presence of ultraviolet light, these films would help to remove bacteria, viruses, and trace organic contaminants from the water.

Material systems that contain TiO2 have been observed to be photocatalytic and, in particular, to be photocatalytically effective for destroying organic compounds. Bacteriocidal films containing TiO2 have been made, but, heretofore, have not been exploited for bacteriological protection of drinking water.

A glass bottle to be coated on the inside would be filled with a fluid suspension of TiO2, then inverted. By controlling the rate of release of the suspension, one would control the thickness of the TiO2 film deposited on the inner surface of the bottle. The bottle could then be fired to produce a stable, photocatalytically active TiO2 film.

Coating with TiO2 may also offer an additional advantage by impeding the dissolution of silica from the glass. TiO2 is not toxic, and its solubility is much less than that of SiO2.

This work was done by Anders W. Andren, David E. Armstrong, and Marc A. Anderson of the University of Wisconsin – Madison for Johnson Space Center. For further information, contact the Johnson Commercial Technology Office at (281) 483-3809.