Impact of Nanoparticles Shape and Dye Property on the Photocatalytic Degradation Activity of TiO2

Chemical and physical treatments of commercial titanium dioxide (TiO2) was carried out in this study to generate the shapes suitable for the photocatalytic degradation of Methyl Orange (MO), Congo Red and Methylene Blue which are anionic and cationic dyes respectively. The synthesized TiO2 was characterized using scanning electron microscopy (SEM), X-ray diffractometer (XRD) and Fourier transform infrared spectroscopy (FTIR) and then used under simulated sunlight for the degradation of dyes. The SEM results showed that smaller particles of TiO2 were formed after heating while the chemical treatment resulted in the formation of square-like particles. The XRD results showed that treatments resulted in the dominance of anatase phase and occurrence of the brookite phase. Various concentrations of dyes were considered to assess the photocatalytic degradation capacity and adsorption behaviour of TiO2. The experiments were carried out in a lightproof chamber with a 92.4 % simulation of sunlight. It was found that up to 60 % more degradation takes place in cationic dyes than anionic dyes, because of higher adsorption preceding the degradation. A small particle with a high anatase phase is also more effective for most dyes than other particles under sunlight like conditions. Thus the commercial TiO2 is the most effective TiO2 particle to use for photocatalytic degradation under sunlight like conditions.