Ba0.5Sr0.5TiO3/BaFe12O19 magnetic separation photocatalysts: Structural, optical, microstructure, photocatalytic activity, degradation pathway and mechanism

Abstract

The Ba0.5Sr0.5TiO3/BaFe12O19 (BST5/BFO) magnetic photocatalysts were constructed by a polyacrylamide gel route combined with low temperature heat treatment process. The effect of different BFO contents on the phase, surface microstructure, magnetic and optical properties, and photocatalytic efficiency of BST5/BFO magnetic photocatalysts was investigated. The BST5, BFO and BST5/BFO magnetic photocatalysts were evaluated for the degradation of tetracycline hydrochloride (TC) under simulated sunlight irradiation for 120 min, pH=5, catalyst content of 1 g/L, initial TC concentration of 50 mg/L and the photocatalytic efficiency trend followed the order: pristine BFO < pristine BST5 < BST5/20%BFO < BST5/15%BFO < BST5/5%BFO <BST5/10%BFO. The improvement of photocatalytic efficiency of BST5/BFO magnetic photocatalyst is mainly attributed to the synergistic effect of optical absorption coefficient, squareness ratio (SQR), interface charge transfer and separation efficiency due to the impurity defect and magnetic field induced the formation of oxygen vacancy, hole, hydroxyl radical and superoxide radical. The reasonable photocatalytic mechanism of BST5/BFO magnetic photocatalysts and possible intermediate products were elucidated in detail on the basis of the first principles calculation, capture experiment, radical verification experiment, magnetic data and liquid chromatography-mass spectrometry.