Developing a sharp cone war hammer-like MIL-88A/Ag/MIL-88B Z-scheme heterojunction by a controlled in situ semi-conversion strategy: adsorption–photodegradation of meloxicam and antibacterial activity

Abstract

The development of materials with dual degradation/antibacterial abilities is a promising strategy for environmental governance. In this study, a sharp cone war hammer-like all solid-state Z-scheme heterojunction MIL-88A/Ag/MIL-88B (MAM) was prepared through nano-confined encapsulation and in situ semi-transformation strategies. This method synthesizes mesoporous MIL-88B, and then encapsulates silver nanoparticles (Ag NPs) in the pores of MIL-88B through nano-confined encapsulation. Through controllable in situ disassembly and reconstruction, the conical prismatic MIL-88A was grown on the surface of Ag/MIL-88B to form MAM without an additional Fe source. The material not only significantly inhibits the recombination of electron–hole pairs through a strong interfacial couple, but also greatly enhances the SPR and electron channel interaction of Ag NPs, which significantly improves the light absorption and charge transport efficiency. The nanoconfinement and transformation processes simultaneously increase the pore volume and specific surface area of the material, thereby improving its adsorption ability. Its unique conical mace shape not only facilitates the exposure of more active sites, but also facilitates the penetration of bacterial membranes. MAM-30 showed excellent removal ability of meloxicam (MLX) under visible light by adsorption–photocatalysis (96.08%, 60 min). T.E.S.T., wheat, and mayaquatic hairgrass growth experiments indicated that the toxicity of the MLX solution was significantly reduced after photocatalysis treatment. Meanwhile, MAM-30 can completely inactivate E. coli, S. aureus, and MRSA within 60 min. The mechanisms of adsorption, degradation and antibacterial activity were analyzed. This paper provides new ideas for the development of photocatalytic degradation of pollutants and antibacterial materials based on metal–organic framework materials.