The degradations of aqueous solutions of 2-phenyl-5-sulfobenzimidazole acid (PBSA) using peroxymonosulfate (PMS) activated with LaCoO3 (LCO)-based perovsldte oxides prepared by three different methods (including normal precipitate method named as LCO, introduction of cetyltrimethyl ammonium bromide (CTAB) named as LCO-CTAB and hydrothermal method with the adding of silicon named as LCO-SiO2) were investigated. The results showed that all the catalysts effectively degraded PBSA. At neutral pH, a removal efficiency of about 100% was achieved in less than 10 min. LCO-SiO2 showed the widest solution pH range (4.0-8.0) with a lowest leaching of cobalt and lanthanum ions (both less than 5.0%). The surface and structural properties of the catalysts were determined using X-ray diffraction, N-2 adsorption-desorption, transmission electron microscopy, and X-ray photoelectron spectroscopy. The reaction involved LCO and LCO-CTAB was a combination reaction including homogeneous and heterogeneous reactions. The first one was caused by the leached cobalt ions; the later one was derived by the surface cobalt oxygen bond. In the process of LCO-SiO2 activated PMS, the heterogeneous activation reaction dominated PBSA degradation, which was derived by SO4 and electronic transfer confirmed by the effect of radical quenchers and intermediates identification. Eight intermediates generated from PBSA degradation were identified using gas chromatography-mass spectrometry. The identification of HO3SO- among the products confirmed the proposed SO4 degradation mechanism. (C) 2016 Elsevier B.V. All rights reserved.