Persulfate activation for efficient degradation of norfloxacin by a rGO-Fe3O4 composite

Abstract

Abstract An environmental friendly magnetic reduced graphene oxide nanosheet-iron oxide (rGO-Fe3O4) composite was synthesized by co-precipitation method. Unlike other methods, we only added ferric iron to form Fe3O4, and also used much less reduced graphene oxide during the synthesis. The prepared rGO-Fe3O4 could effectively activate persulfate (PS) for the degradation of norfloxacin (NOF) and be easily recovered through magnetic separation. The effects of catalyst dosage, PS dosage, initial NOF concentration and initial pH were evaluated. Degradation experiments showed that the removal efficiencies of NOF and TOC were 89.69% and 45.69% within 75 min, respectively. The degradation intermediates of NOF were identified by HPLC-MS and the degradation pathways were also proposed. The quenching experiments indicated that there were three reactive active species, sulfate radical (SO4•−), hydroxyl radical (•OH) and singlet oxygen (1O2) generated in rGO-Fe3O4/PS system, in which 1O2 was the dominant active species for the degradation of NOF. The recycling test shows that rGO-Fe3O4 composite has good stability, showing a promising application.