Enhanced photocatalytic performance and persulfate activation properties by BiOBr supported waste rock wool fibers under LED blue light

Abstract

An advanced oxidation process was developed under LED blue light (BL) photocatalysis in the presence of ammonium persulfate (APS) for effective degradation of tetracycline (TC) from contaminated water. Waste rock wool (RW) fibers modified with BiOBr nano-sheet (BiOBr/RW) using impregnation combined with hydrolysis process, was employed to activate APS to produce reactive radicals under LED BL irradiation (BiOBr/RW+APS+BL system). The influence factors on TC degradation were investigated. Besides, the radical scavengers such as methanol (MA), phenol (PN), tertbutanoland (TBA) and ethylene diamine tetraacetate (EDTA-2Na) combined electron spin paramagnetic resonance (EPR) analysis were used to confirm the reactive radical species. The developed BiOBr/RW+APS+BL system exhibited much higher TC removal efficiency compared with other reported oxidation systems. In addition, the BiOBr/RW could directly activate the APS leading to degrade TC in the darkness. A maximum TC removal of 84.3% was achieved under the optimal conditions such as initial concentration of APS 100 mg/L, BiOBr/RW dosage 0.1 g/L and pH 7 in 80 min. Results also ascertained that h+, •OH and •SO4- over surface of the BiOBr/RW were the primary active chemical species in the BiOBr/RW+APS+BL system. It was found that the •OH and •SO4- in solution play critical roles for degradation of TC on the BiOBr/RW+APS system in dark. Finally, the repeated experiments indicated the excellent stability, photocatalytic ability and cycling property of BiOBr/RW.