Synergistic Effect between TiO2, Zirconium and Carbon in the Photodegradation of Methyl Orange and Methylene Blue

The photocatalytic behaviour of TiO2 prepared from titanium (IV) ethoxide was determined with regard to the decomposition of methyl orange (MO) and methylene blue (MB) dyes, respectively. In addition, we compared the behaviour of TiO2 photocatalysts prepared in a similar fashion but which were (1) doped with different amounts of zirconium, (2) mixed with active carbon and (3) doped with different amounts of zirconium and mixed with active carbon. All of the TiO2 samples were found to be mesoporous with some microporosity having an average particle size between 200 and 500 nm and with anatase crystallographic modification. The kinetics of the MO and MB dyes' photocatalytic degradation fitted well with the Langmuir-Hinshelwood model and were found to follow pseudo-first-order kinetics. The rates were highest for the TiO2 samples doped with both Zr and mixed with the activated carbon. Characterization of these TiO2 photocatalysts was carried out by X-ray diffraction, scanning electron microscopy and adsorption studies.