Microwave degradation of methyl orange dye in aqueous solution in the presence of nano-TiO2-supported activated carbon (supported-TiO2/AC/MW)

Highlights: ► Nano-TiO2-supported activated carbon (TiO2/AC) was developed and applied to enhance microwave (MW) degradation of azo dye in aqueous solution. ► The supported-TiO2/AC displayed higher catalytic activity than AC alone under MW irradiation. ► The effects of supported-TiO2 content, MW irradiation time, C0, catalyst dose and pH on the degradation extent were assessed. ► The supported TiO2 on AC can be excited to help generate hydroxyl radical in aqueous solution under MW irradiation. - Abstract: In this study, nano-TiO2-supported activated carbon (TiO2/AC) was developed for the microwave (MW) degradation of an azo dye, methyl orange (MO), selected as a model contaminant in aqueous solution. The effects of selected process parameters such as supported TiO2 content, MW irradiation time, initial MO concentration, catalyst dose, and solution pH on the degradation were assessed in detail. The results showed that the supported TiO2 on AC could be excited resulting in the production of hydroxyl radical (·OH) in aqueous solution under MW irradiation, which significantly enhanced the performance of AC/MW process for the degradation of MO. Also, the supported-TiO2/AC displayed higher catalytic activity than AC alone under MW irradiation. By comparison, the supported-TiO2/AC/MW process exhibited several advantages, including high degradation rate, short irradiation time, no residual intermediates and no secondary pollution. Hence, it shows to be a promising technology for the destruction of organic contaminants in dye treatment applications.