Microwave induced degradation of parathion in the presence of supported anatase- and rutile-TiO2/AC and comparison of their catalytic activity

In this study, nano-sized anatase or rutile TiO2-supported activated carbon (A-TiO2/AC or R-TiO2/AC) was developed for the microwave (MW)-induced degradation of parathion as a model contaminant in aqueous solution. The effects of selected process parameters such as anatase or rutile TiO2 content, heat-treatment temperature and time, MW irradiation time, initial parathion concentration, catalyst dose, solution pH and MW power on the degradation were studied in details. The results showed that the anatase- and rutile-TiO2 supported on AC both significantly improved the MW/AC degradation effect and the supported A-TiO2/AC showed higher MW catalytic activity than R-TiO2/AC. Also, the supported A-TiO2 on AC can be excited leading to the production of more hydroxyl radicals (OH) than the supported R-TiO2 on AC in aqueous solution under MW irradiation. Comparatively, the supported A-TiO2/AC/MW process displayed many advantages such as high degradation rate, short irradiation time, no residual intermediates, and no secondary pollution. Therefore, the supported A-TiO2/AC/MW showed to be a promising technology for the removal of parathion in wastewater treatment applications. (C) 2013 Elsevier B.V. All rights reserved.