Magnetic iron phosphide particles mediated peroxymonosulfate activation for highly efficient elimination of sulfonamide antibiotics.

• The Fe x P/PMS system was firstly presented for elimination of sulfonamides and exhibited favorable catalytic activity. • The Fe x P particles presented a unique spherical coralloid morphology structure. • The magnetically separable catalyst exhibited favorable reusability. • OH, SO 4 −, 1O 2 and O 2 − contributed to the elimination of sulfonamides. Transition metal phosphides (TMPs) have emerged as a promising catalyst in the environmental catalysis field due to the excellent catalytic property, high conductivity and long stability. Herein, spherical-coral-like iron phosphide (Fe x P) particles contained FeP orthorhombic crystals and Fe 2 P hexagonal crystals were innovatively constructed by a facile low-temperature phosphating synthesis strategy. This novel heterogeneous catalyst with unique morphology was firstly employed for peroxymonosulfate (PMS) activation to eliminate SDZ. It was turned out that Fe x P possessed favorable catalytic activity for activating PMS and could eliminate SDZ up to 98.2% within 24 min. Compared with Fe 2 O 3 without further phosphatization treatment, the introduction of phosphorus in Fe 2 O 3 significantly ameliorated the catalytic activity for the elimination of SDZ and the apparent rate constant (k obs) increased by 9.1 times. More importantly, the Fe x P particles exhibited magnetic property which is convenient for recycling use. This feature is very different from the previously reported TMPs catalytic materials. Besides, four types of reactive oxygen species (ROS) including sulfate radical (SO 4 −), hydroxyl radical (OH), singlet oxygen (1O 2) and superoxide radical (O 2 −) were detected to play a key role in SDZ elimination by electron paramagnetic resonance (EPR) cooperated with radical quenching tests. This finding opened up an avenue for developing and utilizing TMPs catalytic materials in the environmental remediation. [ABSTRACT FROM AUTHOR]