Recyclable Flower-like Fe3O4@SiO2@NiO Nanoparticles for Rhodamine B Adsorption and Photocatalytic Degradation

Tremendous efforts have been dedicated to developing waste dye treatment methods that are recyclable and efficient. However, challenges such as high toxicity, poor dispersion in aqueous solutions, and the high residual rate problems of some catalysts persist. Herein, inspired by the superparamagnetic properties and the electrostatic absorption capacity of Fe3O4 and the photocatalytic activity of NiO, flower-like, adsorptive-photocatalytic dual-effect dye scavengers, named Fe3O4@SiO2@NiO magnetic nanoparticles (FSN MNPs), are fabricated. The outermost NiO layer with a large specific surface area of 211.876 m2/g effectively adsorbs dyes via electrostatic interactions. More importantly, the introduction of an inert protective SiO2 layer between the Fe3O4 core and NiO shell enhances the chemical stability and catalytic performance of the FSN MNPs. These FSN MNPs are recyclable and can be reused at least six times. Their photocatalytic activity against rhodamine B (RhB) was assessed. They show a high RhB degradation efficiency of up to 99.50%. Therefore, the FSN MNPs are promising catalysts for dye degradation in industrial wastewater treatment applications.