Carbon-Doped Titanium Dioxide Nanoparticles Mediated Photocatalytic Degradation of Azo Dyes Under Visible Light

Visible-light active carbon-doped titanium dioxide (C-TiO2) powders were prepared through sol-gel method and were characterized using powder X-ray diffraction and UV-vis diffuse reflectance spectroscopy techniques. Photocatalytic activity of the prepared catalyst toward the photodegradation of azo dyes, Reactive Red 180 and Reactive Red 141, in the presence of visible light was evaluated. C-TiO2 exhibited enhanced degradation of the dyes compared to Degussa P25 TiO2 nanoparticles. The potential of sulfate radical-producing oxidants (oxone (potassium peroxomonosulfate, PMS), potassium peroxodisulfate) in improving photodegradation of model pollutants has been studied in detail. More than 95 % decolorization of model pollutants was achieved within 20 min in the presence of PMS and the prepared catalyst. The effectiveness of the process has been evaluated by measuring the degree of mineralization of the total organic carbon, a complementary indicator of the treatment efficiencies.