Study On Typical Endocrine Disrupting Chemicals Degradation In The Heterogeneous Fenton-like Reaction Over The P-Doped Fe Single-Atom Catalyst

The continued release of new pollutants into the ecosystem has become a global concern due to their toxicity and persistence.The potential toxicity of bisphenol A(BPA),a recognized endocrine disruptor of estrogen,is an environmental health concern that cannot be ignored.The heterogeneous Fenton-like system is a green and efficient technology for water treatment.Single-atom catalysts(SACs)are widely used in heterogeneous Fenton-like system for the degradation of new pollutants due to their advantages of maximum atom utilization,strong interfacial interactions and welldefined active centers,and good catalytic performance.In this paper,we address the problems of excessive adsorption energy for pollutants caused by the M-N4 symmetric coordination configuration of SACs in heterogeneous Fenton-like system and low loading of active components in SACs,and construct efficient and stable heterogeneous Fenton-like system by modulating the surface electronic structure of SACs through heteroatomic P doping.The P and N co-doped Fe-SACs(Fe-N/P-C SAC)were designed by polypyrrole hydrogel method to modulate the electronic structure of the Fe-active site and enhance the reaction kinetics of peroxymonosulfate(PMS)activation.Fe-N/P-C SAC exhibited an ultra-low activation energy(ca.3.7kJ/mol)and excellent degradation efficiency for BPA over a wide pH range(4.3-9.2).The excellent reaction kinetics of Fe-N/P-C SAC was attributed to the enrichment of the electron density of Fe atoms by P-doping,which resulted in the formation of a dual electron-rich Fe and electrondeficient P reactive site and accelerated the electron conversion process to reactive oxygen species(ROS).Highly loaded xFe-N/P-C SACs were synthesized by coordination design strategy.The xFe-N/P-C SAC with high loading showed good performance in the degradation of BPA by heterogeneous Fenton-like activated PMS.The BPA removal showed a "volcanic" variation with increasing loading,and the optimal loading of Fe was 4.72wt.%,which could completely decompose BPA in only 10 min.4.72wt.%FeN/P-C SAC also showed a good removal effect on dissolved organic matter(DOM)in the effluent of a sewage treatment plant.The xFe-N/P-C/PMS system had a more significant removal effect on the biotoxic fluorescent direction protein.With the increase of the loading amount,the highly loaded xFe-N/P-C/PMS system was transformed from a non-radical pathway to a free radical pathway,and the dominant ROS is transformed from 1O2 to HO2·/O2·-.Therefore,this study has developed a highly loaded heteroatom-doped Fe SACs that can be applied to actual water bodies,resist environmental interference,and have a rapid reaction rate,which provides an idea for constructing an efficient heterogeneous Fenton-like reaction system.