Design and development of novel titania nanotubes based photo(electro)catalytic reactor

A new highly-efficient photo(electro)catalytic reactor for water and air purification was designed and assembled based on photoelectrocatalytic technology to completely degrade organic pollutants without any hazardous oxidants. The active part of the reactor consists of nanosized titanium dioxide, which is illuminated with UV light, hence generating electrons and holes that take part in the oxidation and reduction reactions at the semiconductor’s surface. Since titania nanotubes film is grown by anodic oxidation process it is consequently firmly attached to different forms and shapes of metal titanium and cannot be washed away during the treatment. In our work we studied the most important parameters of anodic oxidation and annealing procedure that determine the morphology, length, and crystal structure of polycrystalline TiO2 nanotubes. We found out that the optimum length of titania nanotubes is between 15 to 20 µm which enables effective capture of the incident UV illumination and control of electron-hole recombination time. The efficiency of thus processed active photocatalytic parts was measured via degradation studies of caffeine and phenol. These active photocatalytic anodes were later assembled into a large-volume reactor (1.5 l) and positioned next to metal cathodes and UV light sources in such a way to achieve a uniform illumination of the photocatalyst. Currently, this large-volume reactor is tested to degrade organic compounds present in real waste waters from textile, pharmaceutical and paper production industries.