Sonochemical degradation of reactive black 5 with a composite catalyst of TiO₂/single-walled carbon nanotubes

In the sonocatalytic process, composites of TiO₂-carbon were used because carbon provides more adsorption sites and acts like an electron sink to prevent the recombination of an electron/hole. Therefore, in the present study, the characteristics of a TiO₂/single-walled carbon nanotubes catalyst (TiO₂/SWCNTs) have been investigated, and the optimal weight ratio of SWCNTs and the dose for degradation of reactive black 5 (RB5) were also evaluated. TiO₂/SWCNT composite was characterized using Brunauer-Emmett-Teller analysis, scanning electron microscopy, energy-dispersive X-ray diffraction microanalysis and spectra, and X-ray diffraction patterns. The degradation rate constants of RB5 with the ratio of SWCNTs were found to depend on the adsorption phenomenon of a surface catalyst, light absorbance, and the recombination of electrons and holes. As a result, the optimal ratio of carbon in the sono-TiO₂/SWCNTs process for degradation of RB5 was TiO₂ : SWCNTs = 200 : 1. Additionally, the optimal dose of the catalyst was 0.5 g/L.