Photocatalysts promoted by semiconducting oxides have been intensively studied in the last decades; semiconductor heterogeneous photocatalysis has enormous potential as a process to treat organic contaminants, both in water and in air. Photocatalysis is part of the advanced oxidation processes (AOPs), techniques based on the generation in aqueous solutions of highly reactive hydroxyl radicals, able to promote oxidation a wide range of organic compounds.
Among AOPs, heterogeneous photocatalysis have been proved to be of interest due to its efficiency in degrading recalcitrant organic compounds. Several semiconductors (TiO2, ZnO, Fe2O3, CdS, ZnS) can act as photocatalysts but TiO2 has been most commonly studied due to its higher stability as well as higher efficiency in degrading organic pollutants and achieving mineralization. Photocatalytic and hydrophilic properties of TiO2 makes it close to an ideal catalyst due to its high reactivity, low toxicity, high chemical stability and relatively limited costs.
In our laboratory, the main application based on photocatalysis is the use of titanium dioxide immobilized into a multilayered transparent fluoropolymeric matrix. Using a simple batch reactor, this unique photoactive coating can be applied directly on the UV source. The coated UV lamp can be immersed into polluted aqueous solutions, allowing the photocatalyst to be effective both in clear and in highly turbid conditions.