SnO₂-Fe₃O₄ nanocomposites for the photodegradation of the Congo red dye

Synthesis of SnO₂-Fe₃O₄ nanocomposites was conducted. The purpose of this study was to obtain the SnO₂-Fe₃O₄ nanocomposites, the effectiveness of photodegradation Congo red by SnO₂-Fe₃O₄ nanocomposites and determine the kinetics of photodegradation. The XRD analysis showed that the SnO₂-Fe₃O₄ nanocomposite best mass ratio was 1:1 based on the highest intensity of characteristic angle (2θ), which is 26.54° and had the smallest crystal size, which is 9.662 nm. Based on the UV-Vis DRS result, the SnO₂-Fe₃O₄ nanocomposites bandgap value was 2.3 eV. The magnetization saturation value of SnO₂-Fe₃O₄ nanocomposites was 64.96 emu/g. The morphology of SnO₂-Fe₃O₄ nanocomposites showed by the TEM image, where the dark spots spread in the lighter areas. The surface of SnO₂-Fe₃O₄ nanocomposites characterized by SEM with the result was bumpy surface and many pores. The EDS result of SnO₂-Fe₃O₄ nanocomposites confirmed the presence of Fe, Sn, and O elements. The functional group of SnO₂-Fe₃O₄ nanocomposites showed by FTIR data, the stretch band of Sn-O characteristics showed at wavenumber 590 cm^-1, and the stretch band of Fe-O showed at wavenumber 563 cm^-1. The optimum condition of nanocomposites at a contact time of 90 min and the optimum concentration of 18 mg/L showed that the percent of photodegradation was 50.76%. The photodegradation rate of SnO₂-Fe₃O₄ was fitted to Pseudo-second-order.