PHOTOCATALYTIC PERFORMANCE OF TiO2 COATED CERAMIC TILES

Abstract

In this work, commercially available titanium dioxide (TiO2, 25nm) and Si-modified TiO2 nanoparticles have been deposited on ceramic tiles by spray coating method to product photocatalytic active surface. Phase analyses of the powders and microstructure of the photocatalytic surfaces were characterized with X-ray diffraction method (XRD) and scanning electron microscopy (SEM) respectively. In order to evaluate the photocatalytic activity of the uncoated, unmodified TiO2 coated and Si-modified TiO2 coated tiles, methylene blue was used as organic pollutants for the photocatalytic experiments. Thus, methylene blue aqueous solutions were prepared in 5mg/L, 15mg/L and 30mg/L concentrations by dissolving the dye in distilled water. All polluted tiles were placed under direct sunlight irradiation for 120min. Color values of the tiles were recorded by CIE (L,a,b) colorimetric standard system for before photodeposition, after pollution and after photodeposition. The results revealed that, Si-modified TiO2 coated tiles have shown better photocatalytic activities than uncoated and unmodified TiO2 coated tiles. It showed that, nearly 100% cleanability degree were observed for Si-modified TiO2 coated tiles in 80, 100 and 120 min for 5-15 and 30mg/L methylene blue concentrations respectively. On the other hand no completely cleaning was detected for uncoated and unmodified TiO2 coated tiles for all methylene blue concentrations.