In this study, the previously overlooked effects of contaminants molecular structure on their degradation efficiencies and dominant reactive oxygen species (ROS) in advanced oxidation processes (AOPs) were investigated with peroxymonosulfate (PMS) activated system selected as the typical AOPs system. Averagely, degradation efficiencies of 19 contaminants were discrepant in the CoCaAl-LDO/PMS system with production of SO4●−, ●OH and 1O2 following the order: carbamazepine (CBZ)-like &gt; bisphenol &gt; sulfanilamides (SAs) &gt; triazine &gt; tetracyclines &gt; quinolones compounds. Density functional theory (DFT) calculations indicated that compounds with high energy of highest occupied molecular orbital (EHOMO) , low energy gap (Δ = ELUMO – EHOMO), and low vertical ionization potential (VIP) were more vulnerable to be attacked. Further analysis disclosed that the dominant ROS was the same when treating similar types of contaminants, namely SO4●−, 1O2, 1O2 and ●OH for the degradation of CBZ-like, SAs, bisphenol and triazine compounds, respectively. This phenomenon can be explained from the following two aspects: firstly, it’s discovered that the commonly-shared or basic parent structures of contaminants were usually the main sites that were easily and initially attacked by ROS; secondly, the molecular structure of a contaminant was found to affect its effective reaction time (ERT) and second-order rate constants with ROS, thus influencing the contribution of each ROS during its degradation. Theoretically, the one possessing a longer ERT is more likely to be the dominant ROS responsible for the corresponding contaminant degradation. Overall, the new insights gained in this study provide a basis for designing more effective AOPs to improve their practical application in wastewater treatment.

Effects of molecular structure on organic contaminants degradation efficiency and dominant reactive oxygen species (ROS) in advanced oxidation process with multiple ROS

Fall 2022 abstracts, posters, and presentations will launch in mid-September.

ACS Fall 2022

The official archive and repository for all ACS Meetings & Expositions abstracts and select posters or presentations.