Photodegradation behaviour of multiclass ultraviolet filters in the aquatic environment: Removal strategies and photoproduct identification by liquid chromatography-high resolution mass spectrometry.

Different photodegradation strategies were assessed to remove 21 multiclass organic ultraviolet (UV) filters including benzophenone-, camphor-, and p-aminobenzoic acid- derivatives, methoxycinnamates, and salicylates, among others, from the aquatic environment. Direct photolysis under UVA (λ = 365 nm) and UVC (λ = 254 nm) radiations and advanced oxidation processes (AOPs) based on heterogeneous UVA/TiO2 photocatalysis and the UVC/H2O2 system were applied for the degradation tests. LC-MS/MS and SPME-GC-MS/MS were employed for the monitoring of the target compound degradations. UVC photolysis provided the highest removal efficiency for most of the studied UV filters with degradation yields higher than 90% after 60 min of light exposure in ultrapure water. This radiation was also applied to different real water matrices (river, sea, and swimming-pool water), showing that the degradation yield was dependent on the water matrix, being more difficult the removal of the target compounds in waters with high organic matter content. In an attempt to accelerate the degradation of the studied compounds in this kind of water matrices, the use of a powerful UVC/H2O2 system improvement the reaction kinetics, showing degradation > 90% for most of the studied UV filters. Besides, up to 19 photoproducts could be identified by HRMS.