Overview of the Phototransformation of Wastewater Effluents by High-Resolution Mass Spectrometry

Photochemical transformation driven by sunlight is one of the most important natural processes for organic contaminant attenuation. In the current study, statistical analysis-assisted high-resolution mass spectrometry was employed to investigate the phototransformation of nontarget features in wastewater effluents under various radical quenching/enhancing conditions. A total of 9694 nontarget features were extracted from the effluents, including photoresistant features, photolabile features, and transformation products. 65% of the wastewater effluent features were photoresistant, and the photolabile features could be classified into five groups: direct photolysis group (group I), HO•-originated species-dominated group (group II), 3OM*-dominated group (group III), photochemically produced reactive intermediates combination-dominated group (group IV), and non-first-order degradation group (group V). The direct photolyzed features were observed to degrade significantly faster than the indirect photolyzed fea...