BN/Fe₃O₄/MIL-53(Fe) ternary nanocomposite for boosted ibuprofen degradation by visible light assisted photocatalytic activation of persulfate

In this paper, ternary nanocatalysts BN/Fe3O4/MIL-53(Fe) (BNCFe) were derived from ion-based metal organic framework (MIL-53(Fe)) and boron nitride (BN) composites through calcination, and used for the photocatalysis of ibuprofen (IBP) with the addition of persulfate (PS). After calcination, the obtained BNCFe composites had roughly surface structure, larger aperture and narrower band gap compared with BN/MIL-53(Fe), which could improve the photocatalytic performance of the composites. The coexistence of BN, Fe3O4 and MIL-53(Fe) in the synthesized catalyst was confirmed by X-ray diffraction (XRD) and X-ray photoelectron spectroscopy (XPS) characteristics. BNCFe composites obtained at calcination temperature of 350 degrees C showed the best catalytic ac-tivity and the degradation efficiency of IBP reached 100% within 180 min. The addition of HCO3- hindered the decomposition of IBP, while Cl- promoted the degradation efficiency of IBP at low concentration and inhibited it at high concentration. In addition, quenching experiments and electron spin resonance results showed that three strong oxidizing free radicals (O-2.(-), .OH and SO4.(-)) played a crucial role in the photocatalytic process. Finally, the distribution of electrostatic potential showing that the side chain was the most easily attacked sites of free radicals, and the reasonable degradation pathways of IBP were proposed based on the intermediate product analysis and density functional theory (DFT) calculations. It was expected that this BN/Fe3O4/MIL-53(Fe) (BNCFe) ternary heterojunction photocatalyst would be a promising candidate for IBP treatment.