Effects of molecular structure and existing forms on degradation of emerging contaminants by LaFeO3/NDA−99−oxygen vacancy−driven photo−Fenton system

Abstract

The selective elimination of emerging contaminants (ECs) by means of advanced oxidation processes is gaining more and more interest. The LaFeO3/NDA−99−oxygen vacancy−driven photo−Fenton system was chosen as a typical advanced oxidation process to investigate the effect of the previously neglected ECs molecular structure and existing forms on the degradation efficiency. Tetracycline antibiotics (TCs), quinolone antibiotics (QNs) and sulfonamide antibiotics (SAs) were used as target contaminants. TCs were found to have removal efficiencies more than 85.00% (91.52%, 88.68%, 86.55%, and 85.83%). Three parameters ((energy gap (ΔE, 27.50%), energy of the highest occupied molecular orbital (EHOMO, 17.00%), vertical ionization potential (VIP, 17.00%)) obtained the highest contributions (61.50% in total) on the removal efficiency. The effect of the existing forms on the removal efficiency in different pH was also explored. ECs in neutral form are more easily degraded. DFT calculation may anticipate the degradation pathways of different−structured contaminants based on intermediate detection and analysis. With the new insights gained from this research, wastewater treatment will have a theoretical foundation for optimizing the degradation potential of contaminants with varying molecular structures and existing forms.