Magnetic N-doped graphene with multiple catalytic sites for efficient activiation of peroxymonosulfate

The Fe2O3, Fe3N, single-atom Fe (SA-Fe) and N-doped magnetic graphene (Fe-MNG) were prepared by a facile one-pot method and applied for the activation of perpxymonosulfate (PMS). The results show that Fe-MNG/PMS system was efficient for the oxidative degradation of sulfisoxazole (SIZ) over a wide pH range (3~10) with the removal percentages over 99%. After five cycles, degradation percentages of SIZ maintain over 95% by using the recycled Fe-MNG catalyst. The multiple catalytic sites such as SA-Fe and N of Fe-MNG can effectively activate PMS for the generation of various reactive oxygen species (ROS). Quenching experiment and electron paramagnetic resonance spectroscopy showed that SO4•-, HO• and 1O2 were produced in the Fe-MNG/PMS system, demonstrating the co-existence of free radicals and non-radicals processes. In addition, the Fe-MNG possesses large surface area (446.18m2/g), which can pre-concentrate organic micropollutants onto its surface by adsorption, simultaneously producing a large amount of ROS via PMS activation, leading to the in-situ and high-efficiency oxidation and removal of organic micropollutants. The Fe-MNG also possesses magnetic properties which can be easily recycled, indicating its great application potential.