固相法绿色制备Fe-N-C单原子催化剂及其活化过一硫酸盐连续降解酸性橙7OA

The advanced oxidation process based on peroxymonosulfate(PMS)activation by Fe-N-C single-atom catalysts has garnered wide attention in the field of wastewater treatment.However,two challenges remain to be addressed for its practical engineering application:firstly,the green synthesis of highly active Fe-N-C catalysts,and secondly,the performance evaluation of the Fe-N-C/PMS system for continuous pollutant treatment.Using 2-methylimidazole and zinc/iron oxides as raw materials,a solvent-free green synthesis of Fe-N-C single-atom catalysts was achieved through solid-phase reaction and high-temperature thermal treatment.Furthermore,a conceptual setup for continuous wastewater treatment was designed,employing cotton-supported catalysts as a fixed-bed for PMS activation,achieving nearly 100％removal efficiency in the continuous degradation of acid orange 7(AO7)over 280 h.Structural analysis revealed that the single-atom Fe in the synthesized Fe-N-C catalyst coordinates with either pyrrolic or pyridinic N to form Fe-N4 moieties.Studies indicate that these moieties serve as the primary catalytic sites for PMS activation and works synergistically with adjacent micropores and N-Cx sites to degrade AO7.Quenching experiments demonstrated that singlet oxygen(1O2)is the dominant reactive oxygen species responsible for AO7 degradation.The experimental results on AO7 degradation indicate that the Fe-N-C/PMS system has a broad pH application range(3.0～11.0)and exhibits excellent catalytic degradation performance for AO7 in different water qualities(ultrapure water,tap water,Foshan Qiandeng Lake water).Furthermore,common anions in water bodies(Cl-、SO42-、HCO3-,etc.)have minimal impact on the removal efficiency of AO7 by this system.These results provide valuable insights for further research on the engineering application of Fe-N-C and other transition metal single-atom catalysts(TM-N-C)in advanced oxidation processes.