Box-Behnken design for the optimization of the photocatalytic degradation of methyl orange using gold-platinum bimetallic nanoparticles doped-1D titania

Abstract

The aim of this work is the study the degradation of methyl orange (MO) dye in the presence of materials based on titanate nanotubes (TNT). The nanotubes are synthesized hydrothermally followed by simultaneous deposition of gold and platinum nanoparticles at different content. The characteristics of the obtained materials are determined by: photoelectron spectroscopy (XPS), N2 Adsorption-desorption, X-Ray Diffraction (XRD), High-resolution transmission electron microscopy (TEM), UV–Visible in Reflection Diffuse (RD/UV–Vis) and Fourier-transform infrared spectroscopy (FTIR). The results of this part reveal the formation of nanotubes well decorated by metallic nanoparticles. However, the oxidation of MO is carried out under different conditions: UV, Visible irradiations, and/or in the presence of oxygenated water (H2O2) and at different concentrations of pollutants. The Au-Pt/TNT bimetallic catalyst shows interesting activity in a fairly short time and a mineralization rate that reaches 70 %. Based on ANOVA studies, the results show that the response of degradation rate (R) is considerably influenced by a positive individual effect of methyle orange concentration. However, the individual effect of catalyst weight and oxidant volume has an antagonist impact through the degradation process.