Photoelectrocalytic decontamination of wastewater from emerging organic pollutants : detection of transformation products by high-resolution mass spectrometry (LC-HRMS)

In the last years the release of organic pollutants into the environment, in particular through wastewater, represents a growing problem. A large part of these pollutants belongs to the category of the emerging organic contaminants and are still unregulated or in process of regularization. They are potentially dangerous for human health and living organisms and for this reason their degradation is a huge challenge for the enhancement of the water quality. Among the different approaches that can be used in this regard, advanced oxidation processes (AOPs) represent new and very promising technologies. In the present study, a new photoelectrochemical (PEC) process based on the use of photoactive TiO2 coatings directly grown on titanium wire meshes was developed and employed for carbamazepine removal from wastewater. The detection of transformation products of investigated CECs (contaminants of emerging concern ) was performed by liquid chromatography coupled to high-resolution mass spectrometry (LC-HRMS) analyses by employing a non-target analysis approach based on the processing of accurate MS and MS/MS data by open source databases and software. Conclusions o Photoelectrocatalysis treatment was effective in degrading CECs from secondary effluent wastewater; o The CECs removal efficiency was UV/TiO2+Bias > UV/TiO2 > UV; o The screening for suspect/non-target compounds detection led to the detection of 220 compounds in the starting effluent (62 suspect CECs) and 195 transformation products; o Suspect CECs follows a similar trend of spiked carbamazepine: as number of them was formed and then removed, another group was formed at a later stage and then accumulating in the reaction mixture (especially with UV and UV/TiO2).