Degradation mechanism of tris(2-chloroethyl) phosphate (TCEP) as an emerging contaminant in advanced oxidation processes: A DFT modelling approach

As a typical toxic organophosphate and emerging contaminant, tris(2-chloroethyl) phosphate (TCEP) is resistant to conventional water treatment processes. Studies on advanced oxidation processes (AOPs) degrade TCEP have received increasing attention, but the detailed mechanism not yet fully understood. This study investigated mechanistic details of degradation promoted by OH using density functional theory (DFT) method. Our results demonstrated that in initial step, energy barriers hydrogen abstraction pathways were no more than 7 kcal/mol. Cleavage P–O or C–Cl bond was possible occur, whilst C–O C–C cleavage had overcome an barrier above 50 kcal/mol, which too high for mild experimental conditions. The dissociation (BDE) combined with distortion/interaction (DIE) analysis disclosed origin various reactivities each site TCEP. systematic calculations transformation products generated step showed remarkable exothermic property. novel information at molecular level provides insight how these are offers valuable theoretical guidance help develop effective AOPs other environmental contaminant.