Titania-coated glass microballoons and cenospheres for environmental applications

• Published in: Journal of materials science 2009-03, Vol.44 (6), p.1435-1441
• Main Authors: Koopman, M., Chawla, K. K., Ricci, W., Carlisle, K., Gladsyz, G. M., Lalor, M., Jones, M. L., Kerr, K., George, M. P., Gouadec, G., Tournié, Aurélie
• Format: Article
• Language: English
• Subjects: Aeration; Catalytic activity; Cenospheres; Characterization and Evaluation of Materials; Chemical Sciences; Chemistry and Materials Science; Classical Mechanics; Coatings; Crystallography and Scattering Methods; Drinking water; Energy dispersive X ray spectroscopy; Environmental Sciences; Glass; Industrial wastes; Materials Science; Mechanical properties; Microballoons; Morphology; Nanoindentation; Organic chemistry; Photocatalysis; Polymer Sciences; Procion; Raman spectroscopy; Scanning electron microscopy; Solid Mechanics; Syntactic and Composite Foams; Wastewater treatment; Water purification
• ISSN: 0022-2461; 1573-4803
• DOI: 10.1007/s10853-008-2963-9

Functional titania coatings on glass microballoons (GMBs) and cenospheres have a broad range of potential environmental applications, primarily in purification of drinking water and treatment of industrial wastewater. The heterogeneous photocatalytic capabilities of titania films and particles have been extensively examined in the literature as effective alternatives to current technologies. Although the chemistry of titania films for photocatalysis has been studied, titania-coated GMBs have not yet been extensively considered and the materials science aspects of the titania-GMB and titania-cenosphere systems have not been addressed. We have examined the microstructure, morphology, and mechanical properties of titania coatings on both cenospheres and commercially produced GMBs. Scanning electron microscopy was used to examine coating coverage and defects. Energy dispersive X-ray spectroscopy and Raman spectroscopy were used for element and phase identification, respectively. Hardness and modulus measurements of the titania coatings and the GMB and cenosphere materials were done by nanoindentation. Additionally, the photocatalytic activity of the titania-coated GMB system was tested on Procion Red dye using two different types of mixing, a magnetic stirrer and an aeration bubbler apparatus. The titania coatings showed good coverage and retention except in the case of magnetic stirring, where significant coating loss was observed.