Photo-fixation of Ag onto TiO2 Powder Films for Improved Photocatalytic Activity and Atomic-absorption Determination of Residual Noble Metal in Dyes Solution

Abstract

For the first time, we photo-fixed silver ions (10–2, 10–3, and 10–4 M) onto films prepared from commercial TiO2 powder via ultraviolet illumination. The synthesis process is straightforward and environmentally friendly. The nanostructures are characterized by SEM, XRD, FAAS, and UV/Vis spectroscopy for the photocatalytic properties. The X-ray diffraction pattern demonstrated the phase of the anatase TiO2 structure. Flame Atomic Absorption Spectrometry is used as a simple way to determine the Ag+ content in solutions from the heterogeneous photocatalysis under UV illumination. The research shows that at the end of the degradation process, no silver ions are observed for both dyes – malachite green and methylene blue. The formation of stable intermediates by the reaction of OH with the triarylmethane dye during the photocatalysis resulted in faster degradation of malachite green than methylene blue. In comparison to pure TiO2, the TiO2/Ag films have higher photocatalytic efficiency. The reason is the presence of silver, which leads to a decrease in the recombination of pairs of charges.