Advanced Oxidation Processes Based on Photocatalysis for the Degradation of Organic Contaminants in Water

Many organic pollutants are daily released into the environment or pass through the wastewater treatment plants contaminating surface and drinkable water. Part of these pollutants belongs to the category of the emerging organic contaminants since they are still unregulated or in process of regularization. They give cause of concern since they are dangerous for human health and for the survivor of a large number of living organisms. The implementation of wastewater treatment plants against the emerging contaminants is one of the challenges for the enhancement of the water quality, and advanced oxidation processes represent new technologies very promising as tertiary treatments. The research activity carried out during my PhD course focused on degradation test on aqueous solutions contaminated with different class of pollutants such as surfactants, pharmaceuticals and personal care products, both as single compound solutions and mixture of contaminants. The photocatalytic process was studied developing a new pre-industrial pilot plant and testing new TiO2-based photocatalysts in a view of a technological transfer of the photocatalytic methodology. The reuse of a photocatalyst consisting of TiO2 supported on a solid substrates was also investigated with the aim to avoid some problems related to the use of a dispersed catalyst. Photocatalytic process coupled with ultrasounds was also examined in order to speed up the decomposition of the pollutants. The disappearance of every pollutant was followed by HPLC analysis and the mineralization was assessed by the determination of total organic carbon. In the end, the energy consumption related to the processes tested on the mixture of contaminants was calculated in order to establish the best methodology to obtain good degradation rate with reasonable costs.