Synthesis of Pd-modified Fe3O4 loaded on montmorillonite catalyst for photocatalytic degradation of tetracycline

In this study, a straightforward and effective strategy is presented for the synthesis of Pd -modified Fe3O4 magnetic nanoparticles loaded on montmorillonite (Pd@Fe3O4/MMT). The synthesis process involved using montmorillonite as a template, and Pd@Fe3O4 nanoparticles were uniformly anchored on the surface of montmorillonite. Various characterization results proved the successfully preparation of Pd@Fe3O4/MMT, including transmission electron microscopy (TEM), scanning electron microscopy (SEM), X-ray photoelectron spectroscopy (XPS), etc. The Pd@Fe3O4/MMT was found to possess photocatalytic activity on degradation of tetracycline (TC). Importantly, the introduce of MMT enhanced the catalytic activity due to the increased dispersion of nanoparticles The most favorable conditions were found to be pH 6, a catalyst concentration of 55 mg/L, H2O2 concentration of 0.19 g/mL, and an initial tetracycline concentration of 40 mg/L. Under these conditions, the degradation rate of tetracycline in the aqueous solution exceeded 84 %, indicating the high catalytic efficiency of the Pd@Fe3O4/MMT. The results of the free radical capture experiment and electron spin resonance (ESR) demonstrated that center dot OH radicals were responsible for the tetracycline degradation process. In conclusion, this study offers a simple and effective method for the preparation of Pd@Fe3O4/MMT nanocomposites with excellent catalytic activity for tetracycline degradation in aqueous solutions.