Flower-like hierarchical Sn3O4/montmorillonite nanostructure for the enhanced microwave-induced degradation of rhodamine B

Abstract

A flower-like hierarchical nanostructure of Sn3O4/montmorillonite is first reported in this work. The nanomaterial was prepared by a one-pot hydrothermal synthesis method using tin chloride as the precursor, and the physicochemical characteristics of the material were examined by instrumental analyses. The prepared nanostructure was evaluated as a catalyst in the microwave-induced removal of rhodamine B (RhB). The influences of Sn content, oxidant, time of irradiation, and initial concentration of RhB were investigated. The results showed homogeneously dispersed Sn3O4 in a montmorillonite support with a cubic phase, and crystallite size smaller than to Sn3O4 was obtained. XPS investigation revealed the Sn3O4 phase, which is consistent with the band gap energy of 2.75 eV from UV-DRS measurements. The homogeneous distribution of the Sn3O4 nanoparticles influenced the increasing specific surface area of the nanocomposite compared to montmorillonite. The enhanced physicochemical properties significantly enhanced the catalytic activity in microwave induced RhB oxidation, with the degradation efficiency reaching 99.9% after 20 min of treatment. The kinetics of catalytic oxidation were best fitted to the pseudo-second-order equation and obeyed the Langmuir-Hinshelwood kinetics model. Furthermore, the catalytic oxidation condition optimization using a Box-Behnken Design revealed the contribution of oxidant, pH and catalyst dose as influencing factors for the efficiency.