Synthesis, characterization and catalytic activity of Fe3O4@WO3/SBA-15 on photodegradation of the acid dichlorophenoxyacetic (2,4-D) under UV irradiation

Dichlorophenoxyacetic acid (2,4-D) is an herbicide widely used in extensive agriculture, toxic to humans and other animals, in addition to causing contamination of water resources. The 2.4-D is resistant to conventional degradation processes, in this context, heterogeneous photocatalysis is presented as a promising alternative in the degradation of this type of micropollutant. This work aims to synthesize, characterize and evaluate the catalytic activity of Fe3O4@WO3/SBA-15 in the photodegradation of (2.4-D) under ultraviolet irradiation. The nanomaterials were obtained by the co-precipitation, solvothermal and hydrothermal methods. The XRD patterns showed that the insertion of Fe3O4@WO3 in SBA-15 (5, 10 and 20 %) did not destroy the support mesoporous structure as well as indicated Fe3O4 and WO3 chrystillen phases. The core-shell morphology was confirmed by micrographs (FESEM, TEM and HRTEM) as well as the average size of the particles of WO3 = 35.8 nm and Fe3O4 = 13.3 nm. The energetic gap of nanomaterials were (WO3 = 2.6, Fe3O4 = 2.8, Fe3O4@WO3 = 1.9, Fe3O4@WO3/SBA-15 (5 %). = 2.7, Fe3O4@WO3/SBA-15 (10 %) = 1.7 and Fe3O4@WO3/SBA-15 (20 %) = 1.8). The Fe3O4@WO3/SBA-15 (X%) samples showed magnetic properties and photocatalict efficience for 2,4 D photodegradation under UV irradiation. The Fe3O4@WO3/SBA-15 (5 %) sample has promoted 90.73 % of degradation of the herbicede, at 240 min.