ZIF-8 assisted synthesis of magnetic core–shell Fe3O4@CuS nanoparticles for efficient sulfadiazine degradation via H2O2 activation: Performance and mechanism

A novel magnetic core–shell Fe3O4@CuS have been successfully synthesized by chemical etching and cation exchange method using Zeolitic imidazolate frameworks (ZIF) as the template. The morphology and microstructural properties characterization indicated that Fe3O4@CuS nanoparticles were rhombic dodecahedral shape, highly stable, and magnetic with a large specific surface area (772.20 m2/g). The catalytic activity of Fe3O4@CuS was assessed on sulfadiazine (SDZ) degradation by H2O2 activation. Multi-factors affecting the SDZ removal was adequately investigated. Approximately 93.2% SDZ (50 μM) was removed with 0.2 g/L Fe3O4@CuS and 5 mM H2O2 in 90 min. In particular, Fe3O4@CuS exhibited a quality catalytic performance within a wide pH range of 3.0–11.0. Radical scavenger tests and electron paramagnetic resonance (EPR) analysis confirmed that •O2−, •OH, and 1O2 all contributed to the SDZ degradation, and •OH played the dominant role. Meanwhile, mechanism investigation suggested that the effective catalytic activity of Fe3O4@CuS could be ascribed to the sulphur-enhanced copper-based Fenton reaction on the CuS shell, sulphur-enhanced iron-based Fenton reaction on the Fe3O4 core, and the effective electron transfer between the shell and core. Finally, the possible SDZ degradation pathways were further proposed on the basis of the intermediates identification. This work put forward a new strategy to synthesize magnetic core–shell Fe3O4@CuS using ZIF-8 as the template with outstanding performance for H2O2 activation to degrade SDZ.