The increasing level of pollution in the world represents a problem on which particular attention has been paid in recent decades, thus directing research towards the use of sustainable and efficient technologies for air and water purification. An emerging technology, which is proving to be very effective, is the photocatalytic oxidation.
This technique uses semiconductor materials such as titanium dioxide as photocatalysts. Titanium oxide seems to be the ideal photocatalyst if irradiated by UV radiation and for this reason it was also used in my experimental activity. The work carried out was essentially focused on the study of the photocatalytic degradation kinetics of formic acid. The experimental tests conducted in the laboratory concerned organic substrates that degrade directly without reaction intermediates, such as formic acid. For this purpose, an experimental apparatus operating in batch was used. The samples taken at regular periods were analyzed on a Total Organic Carbon (TOC) meter. To activate the photocatalytic process, two different light sources were used installed in two reactors with different geometry: the flat reactor illuminated with LED technology and the annular reactor illuminated with a fluorescent lamp. The experimental data (concentration of formic acid vs time) were subjected to kinetic analysis. For this purpose the integral method of kinetic analysis was used assuming two different models, to which correspond two different kinetic equations: a kinetic equation with a single parameter of the Minero quadratic “type” and a kinetic equation with two parameters of the type Langmuir Hinshelwood. The regression of the experimental data was very satisfactory and quite similar for both models. An important conclusion is that the photocatalytic degradation of aqueous solutions of formic acid seems to allow the use of the quadratic model to implement “actinometric measurements” of the radiant energy absorbed in the reactor.