Synthesize and application of high entropy single atom catalyst for PMS activation: Performance and mechanism

Diversified pharmaceuticals and personal care products (PPCPs) were developed, and complex wastewater also appeared simultaneously. The development of catalyst for advanced oxidation processes (AOPs) that can adapt to the complex needs of wastewater treatment is urgent. In this study, a high entropy single atom catalyst (HESACs) was synthesized and applied in peroxymonosulfate (PMS)-based AOPs for the removal of acyclovir (ACV). X-ray absorption fine structure, X-ray diffraction, and X-ray photoelectron spectroscopy analysis confirmed the successful synthesis of HESACs. The mechanism of PMS activation was elucidated through quenching studies and electron paramagnetic resonance analysis. During PMS activation in HESACs, ACV undergoes degradation via multiple pathways, including • O 2 − , • OH, SO 4 •− , 1 O 2 , high-valent metal-oxo, and direct electron transfer. These pathways enhance the adaptability of the system to the complex wastewater demands. ACV was completely degraded within 7 min, achieving 28.82 % mineralization within 30 min in the HESACs/PMS system. Furthermore, the system demonstrated higher removal efficiency under alkaline conditions, with degradation efficiency remaining above 90 % after five cycles. The degradation intermediates of ACV were identified, and the degradation mechanism was elucidated. The system is capable of detoxifying ACV. DFT calculations results indicate that regions with negative potential and atoms exhibiting higher f − values in ACV molecules are more prone to attack within the HESACs/PMS system. This study presents the synthesis and application of HESACs in complex water environments for the degradation of PPCPs.