A comparative study of the sonocatalytic degradation of methylene blue by using silicon carbide and titanium dioxide

Abstract

The acoustic catalytic degradation of methylene blue (MB) was studied using silicon carbide (SiC) nanowires and commercial TiO₂ (P-25). SEM images show that the average diameter of SiC nanowires is less than 500 nm and the length is up to tens of microns. XRD patterns and FTIR spectra confirmed the high purity of SiC in the catalyst. The catalytic performance of the two catalysts is better under alkaline conditions. The K_app values (pseudo-first-order kinetics) of the synergistic effects of ultrasonic treatment and adsorption processes using SiC and TiO₂ are 1.36 and 1.31 times the sum of the K_app values of the two separate processes, respectively. This finding indicates that acoustic catalysis can improve the photocatalytic performance of SiC and TiO₂ on MB. Compared with TiO₂, SiC nanowires exhibit better acoustic catalytic performance, and hydroxyl radicals are more significant in the acoustic catalytic degradation of SiC to MB. Meanwhile, hydroxyl radicals play a leading role in the degradation process of MB.