Bi-etched MIL-125 promotes visible-light-driven photocatalytic performance based on the surface plasmon resonance and spatial confinement effects

Constructing stable, efficient, and affordable visible-light-driven catalysts is a promising technique to remediate water pollution from released antibiotics. In this research, etched Bi@MIL-125 composites were manufactured using a simple hydrothermal method, and their photocatalytic efficacy was tested using tetracycline (TC) as the target contaminant. Morphological analyses indicated that Bi nanoparticles (NPs) were consistently wrapped around the MIL-125 surface, introducing mesoporous structures in MIL-125 by Bi etching. Among different mass ratios (Bi: MIL-125), the Bi@MIL-125 sample with a 1:1 mass ratio (BM100) showed the greatest photodegradation rate (98.6 %) of TC upon visible light illumination. The BM100 exhibited the greatest apparent deterioration rate constant for TC (0.036 min −1 ), 74 times higher than that of pristine MIL-125. The absorption enhancement of Bi@MIL-125 in the visible range was ascribed to the surface plasmon resonance effect of Bi NPs. The mesoporous structure of Bi@MIL-125 provided channels through which TC entered the composite's interior, and the confined space enabled more opportunities for the interaction of •O 2 – and h + active species and TC pollutant molecules. In addition, liquid chromatography-tandem mass spectrometry was used to determine potential intermediates of the photodegradation reaction of TC and BM100, and two distinct degradation routes were hypothesized. Ultimately, combining ECOSAR predictions with zebrafish behavioral tests to assess the toxicity changes in degradation processes and the acute and chronic toxic effects on aquatic animals, the inhibition of the locomotive behavior of zebrafish was significantly decreased after 120 min of photocatalytic degradation, suggesting that the BM100 sample can effectively degrade TC and detoxify the aquatic environment.