Activation of persulfate by graphite supported CeO2 for isoniazid degradation

Abstract

Graphite felt (GF) supported cerium oxide (CeO2) composite was prepared by the impregnation method and used to active persulfate (PS) for degradation of isoniazid (INH). The structure and morphology of the catalyst were characterized by X-ray diffraction, X-ray photoelectron spectrum and scanning electron microscope. The effects of some key parameters including initial PS concentration, initial pH value, catalyst dosage, reaction temperature and inorganic ions on INH degradation were investigated in CeO2/GF/PS system. It was found that 94.39% of INH and 89.9% of TOC could be removed within 10 min under the controlled conditions (1.2 g/L CeO2/GF, 0.25 g/L PS, initial pH at 6.8 and temperature at 25 ℃). The degradation intermediates of INH were identified by liquid chromatography-mass spectrometry and ion chromatography, and the possible degradation pathway was also proposed. The radical competition tests indicated that hydroxyl radical (OH), sulfate radical (SO4−), superoxide (O2−) and singlet oxygen (1O2) coexisted in CeO2/GF/PS system, in which OH was the predominated one. The recycling experiment showed the CeO2/GF was an excellently stable catalyst for activation of PS.