Methylene Blue and Phenol Photocatalytic Degradation on Nanoparticles of Anatase TiO_2

摘要

A photocatalyst was obtained by treating the commercial amorphous anatase titanium dioxide with ammonia water. During the preparation of photocatalytic material the optimal conditions of the separation operation were found. The photocatalyst was characterized by UV/VIS-DR, FTIR-DR, and XRD techniques, and high-resolution transmission electron microscopy (HR-TEM). According to the XRD method, the mean crystalline size of TiO_2 was 12.7-13 nm. The particulates were characterized using a particle size analyzer (mean size 195.7 nm). TEM studies presented the morphology of the sample. The photocatalytic activity of the photocatalyst was determined on the basis of the decomposition rate of phenol and azo-dye (methylene blue) under UV irradiation. The pH effects on the photocatalytic degradation were investigated. The degree of the dye and phenol removal in the solutions was measured by UV/VIS spectroscopy and a TOC analyzer. The decomposition of methylene blue increased along with an increase of pH value, whereas the activity of the prepared photocatalyst toward phenol degradation was the highest at pH=6.5. TOC disappearance in solutions of both organic compounds during photocatalytic reaction corresponded to their decrease of concentration, but with a little delay.