Iron phosphide for photo-assisted peroxodisulfate activation in metronidazole degradation

The elimination of pharmaceutical wastewater has aroused great attention because of its environmental and ecological significance. In this work, an efficient photo-assisted FeP/peroxodisulfate (PDS) system was constructed and applied to the degradation of antibiotic. About 98.47 % Metronidazole (MNZ) could be removed by FeP/PDS after 20 min at its natural pH under the irradiation of 10 W fluorescent. The SO 4 •− , HO • and O 2 •− radicals were involved in MNZ degradation, in which SO 4 •− played the major role. Both Fe δ+ and P δ– in FeP as well as surface oxidized ≡Fe 2+ could be used as activity sites to activate PDS. The rate-determining step of Fenton-like reaction (M (n+1)+ → M n+ ) can be accelerated through internal electron transfer of FeP. Moreover, the Fe 2 O 3 /FeP hetero-structure on the surface of FeP particles also took part in PDS activation under light irradiation. This finding illustrates a potential utilization of metal phosphide as a photo-assisted Fenton-like catalyst to remove organic pollutants in the environment.