Magnetically-extractable hybrid of magnetite, mesoporous silica and titania for the photo-degradation of organic compounds in water

• Autor(a) principal: Jorgetto, Alexandre de Oliveira [UNESP]
• Data de Publicação: 2018
• Outros Autores: Milbrat, Alexander, Schneider, José Fabián, Li, Zheng, Giammaria, Guido, Saeki, Margarida Juri [UNESP], Gianeti, Thiago Marcelo Ribeiro [UNESP], Lima, Giuseppina Pace Pereira [UNESP], Pedrosa, Valber de Albuquerque [UNESP], Mul, Guido, Castro, Gustavo Rocha de [UNESP]
• Tipo de documento: Artigo
• Idioma: eng
• Título da fonte: Repositório Institucional da UNESP
• Texto Completo: http://dx.doi.org/10.1016/j.apsusc.2018.06.218; http://hdl.handle.net/11449/180004
• topic: Advanced oxidation process; Anatase crystal growth; Magnetic extraction; MCM-41 silica; Photocatalysis; Titania coating

This work addresses the development of a magnetically extractable magnetite-silica-titania photocatalyst to be applied in the degradation of organic compounds in water. MCM-41 silica was successfully deposited on magnetite, providing large surface area for anchoring of TiOx species, and preventing thermally induced conversion of magnetite to hematite. A good correlation between the calculated values and amount of titania deposited on the silica-covered magnetite particles was obtained for a synthesis route involving the treatment of magnetite-silica in boiling ethanolic Ti-precursor solution. Photocatalytic activity in conversion of 4-chlorophenol could only be observed for compositions containing larger than ∼50 wt% titania, whereas increasing the titania content did not significantly improve performance. Experiments carried out at pH ∼ 3.0 and ∼7.2 demonstrated the performance is relatively pH-independent. The structure activity-correlation of the materials is briefly discussed.