The aim of this investigation was to study the degradation of tributyl phosphate (TBP) in aqueous solution by heterogeneous photocatalysis (UV-C/TiO 2). To perform the investigation, aqueous solutions containing the contaminant were exposed to UV radiation in the absence or presence of TiO 2 in suspension or supported on a Fe-Cr metal alloy plate. TBP analyses before and after the treatment were performed by Ultra-Performance Liquid Chromatography (UPLC) in order to quantify the contaminant degradation. The results showed that the TiO 2 photocatalytic system was able to remove TBP from the solution and the formation of some by-products was observed. TiO 2 photocatalytic systems were able to reduce acute toxicity in an Artemia Salina bioassay according to the increase in LC 50 from 10.2 ± 0.5%(v/v) to 16.9 ± 0.6 %(v/v) for the immobilized system and to levels which were not possible to detect by the applied method any more for the suspension system.

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The present work aims to study the photocatalytic degradation of three organophosphate esters considered environmental emerging contaminants by the UV/H 2 O 2 system with the use of 31 P NMR spectroscopy to investigative their removal after the treatment. Results demonstrated the efficiency of the oxidation system in removing the esters tris(2-butoxyethyl) phosphate (TBEP), tris(2-chloroethyl) phosphate (TCEP) and tributyl phosphate (TBP) from aqueous solutions when they were individually present and mixed. High levels of degradation of these chemicals were achieved, in addition to the good performance of the analytical technique applied in the study, which represents some advantages in comparison with other techniques reported in the literature. An increase in the 31 P NMR signal removal could also be observed when the oxidizing agent concentration increases. Decreases in solution acute toxicity were also verified for both TBP and TBEP treated samples when compared with the samples before the treatment.