Improved stability in SBA-15 mesoporous materials as catalysts for photo-degradation processes

SBA-15 materials were modified with Cr, Ni and Fe and characterized by ICP, SAXS, XRD, N2 adsorption, TPR and UV–Vis DRS. Their photo-catalytic activity was evaluated for the degradation of Acid Orange 7 (AO7) in aqueous suspensions irradiated by artificial UV–Vis light. The results showed that the...

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Bibliographic Details
Published in:Microporous and mesoporous materials 2016-12, Vol.236, p.218-227
Main Authors: Elías, Verónica R., Ferrero, Gabriel O., Oliveira, Rafael G., Eimer, Griselda A.
Format: Article
Language:English
Subjects:
Catalytic properties
Metallic species
Nanostructures
Stability
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Summary:SBA-15 materials were modified with Cr, Ni and Fe and characterized by ICP, SAXS, XRD, N2 adsorption, TPR and UV–Vis DRS. Their photo-catalytic activity was evaluated for the degradation of Acid Orange 7 (AO7) in aqueous suspensions irradiated by artificial UV–Vis light. The results showed that the Cr-modified catalyst exhibited the highest activity. The presence of Cr6+ highly dispersed on the internal surface of the SBA-15 structure would be responsible for this observed behavior. Then, when TiO2 was loaded on this solid, the photo-activity was increased due to a heterojunction effect between the two metals. Moreover, the TiO2 cover resulted in the Cr species protection leading to a notable decrease of the Cr leaching into the reaction medium. In addition, comparing with the already reported results for modified MCM-41 catalysts, the solid synthesized here allowed achieving the solution biodegradability in shorter irradiation periods and could be re-used even after four cycles without loss of activity. Thus, the high performance of this material leads to make it a very promising photo-catalyst for pre-treatment of recalcitrant contaminants present in aqueous effluents. [Display omitted] •Cr/SBA-15 showed the higher photo-activity in the azo-dye degradation.•A heterojunction between Ti and Cr after the TiO2 loading increases its photoactivity.•Cr leaching decrease after TiO2 loading contributed to the catalyst recyclability.•The TiO2/Cr/SBA-15(2.5) maintained its activity after several catalytic cycles.•The biodegradability of the dye solution was achieved in only 5 h of radiation.
ISSN:1387-1811
1873-3093
DOI:10.1016/j.micromeso.2016.09.001