Photocatalytic degradation of 2,4-dichlorophenol over Fe-ZnO catalyst under visible light

Fe-ZnO was synthesized via impregnation and applied to photocatalytic degradation of 2,4-dichlorophenol (2,4-DCP) under visible light. Conditions of Fe-ZnO synthesis which included a Fe content and a calcination temperature were focused. From UV-DRS, visible light absorption of Fe-ZnO samples increased with increasing of Fe content and calcination temperature. TEM images revealed Fe species (FeO, Fe 3 O 4 , and Fe 2 O 3 ) on ZnO as a function of calcination temperature. XANES analysis confirmed the majority of Fe 3+ content. Response surface methodology (RSM) dominating over experimental design and statistical analysis for 2,4-DCP photocatalytic degradation indicated that the high degradation efficiency was associated with calcination temperature of 680–700 °C, Fe content of 4.5–5.0 mol%, and catalyst loading of 1.2–1.8 g L −1 . Moreover, addition of 2mM of K 2 S 2 O 8 in a 5.0Fe-ZnO@700 °C system could enhance the degradation efficiency to a completion within 90 min. The kinetics of 2,4-DCP photocatalytic degradation well fit the Langmuir-Hinshelwood model.