Removal of tetracycline hydrochloride by N, P co-doped carbon encapsulated Fe2P activating PMS: A non-radical pathway dominated by singlet oxygen

Metal phosphides are effective in environmental catalysis to remove pollutants. Herein, a novel magnetic material of Fe2P nanoparticles encapsulated in N, P-doped carbon (Fe/P-NPGC) was successfully fabricated as a peroxymonosulfate (PMS) activation catalyst. Benefiting from the electron-donating ability of Fe2P, Fe/P-NPGC consistently maintains over 90% removal rate of tetracycline hydrochloride (TCH) over a wide pH range. Based on quenching experiments and characterizations, we propose that Fe2P not only activates PMS to generate reactive oxygen species but also promotes Fe (II) regeneration, thus improving the activation efficiency of PMS and generating an efficient non-radical pathway dominated by 1O2. Both Fe2P and graphitic N have excellent interfacial electron transfer efficiency, which improves the self-decomposition activation of PMS to generate 1O2. The catalyst has excellent stability and adaptability under inorganic ions interference and real water environment, indicating that it has excellent potential for practical wastewater treatment.