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Comparative Study of the Photocatalytic Degradation of the Herbicide 2,4-D Using WO3/TiO2 and Fe2O3/TiO2 as Catalysts

Macías-Tamez, R., Villanueva-Rodríguez, M., Ramos-Delgado, N.A., Maya-Treviño, L., Hernández-Ramírez, A.
Water, air, and soil pollution 2017 v.228 no.10 pp. 379
2,4-D, 2,4-dichlorophenol, byproducts, catalysts, crystallites, mineralization, photocatalysis, sol-gel processing, solar radiation, surface area, titanium dioxide, ultraviolet radiation
In this study, a comparison of the photocatalytic activity efficiency of the catalysts WO₃/TiO₂, Fe₂O₃/TiO₂, and TiO₂ in the degradation of the herbicide 2,4-D and its main by-product (2,4-dichlorophenol, 2,4-DCP), under natural sunlight, visible, and UV light, was carried out. The catalysts were synthesized by the sol-gel method. All the catalysts showed anatase crystalline phase, and they exhibited similar values of band gap, specific surface area, and crystallite size; however, different photocatalytic activity was observed under the different light sources. Complete degradation of 2,4-D and near to 89% of mineralization using WO₃/TiO₂ and Fe₂O₃/TiO₂ was achieved after 150 min under solar light, while using TiO₂ sol-gel, lower degradation rate was obtained. By using artificial light (UV and visible lamp), the degradation and mineralization rates were lower than those obtained under natural sunlight. The produced 2,4-DCP intermediate was completely degraded after 240 min under sunlight only with the modified catalysts.