Rare earth doping: a strategy to enhance the catalytic activity of ZnFeO in activating peroxymonosulfate for acetaminophen degradation.

In this paper, ZnFeO was doped by two rare earth metals (La and Pr), and the as-prepared ZnLaFeO and ZnPrFeO were applied to activate PMS for acetaminophen degradation. ZnLaFeO with the largest oxygen vacancy (O) content showed the highest acetaminophen degradation efficacy. About 89.7% of acetaminophen was removed within 60 min in the ZnLaFeO/PMS system. Free radical quenching experiments and EPR tests confirmed that SO˙, ˙OH, O˙ and O were the dominant reactive oxygen species (ROS). The role of La/Pr doping was explored through a series of comparative studies. The results indicated that La doping enhanced the content of oxygen vacancies, accelerated the electron transfer in the system, and thus sharply improved the catalytic performance of ZnFeO. Furthermore, the reusability, universality and actual water environment adaptability of ZnLaFeO were investigated.