resumo
The synthesis of distinct nanocrystalline TiO2 capped ZnS samples was carried out using a chemical deposition method. The materials characterization showed that the presence of ZnS onto TiO2 surface results in a red shift of the material band edge when compared with the initial semiconductor The photocatalytic activity of the prepared nanocomposites was tested on the decolorization of methylene blue (MB) aqueous solutions. The dye photodecolorization process was studied considering the influence of experimental parameters such as catalyst concentration, TiO2/ZnS ratio, pH and methylene blue adsorption rate. The material with the best catalytic activity towards the methylene blue photodecolorization was the TiO2 doped with 0.2% of ZnS. The complete photodecolorization of a 20 ppm methylene blue Solution, at natural pH was achieved in less than 20 min, nearly 70 min faster than the TiO2 photoassisted process. (C) 2008 Elsevier B.V. All rights reserved.
palavras-chave
DECOMPOSITION; NANOPARTICLES; DEGRADATION; PHOTODEGRADATION; PRECURSORS; SPHERES; DYES
categoria
Engineering; Environmental Sciences & Ecology
autores
Franco, A; Neves, MC; Carrott, MMLR; Mendonca, MH; Pereira, MI; Monteiro, OC
nossos autores
Márcia Carvalho Neves
Investigador Auxiliaragradecimentos
O.C. Monteiro thanks Fundacao para a Cinciae Tecnologia (FCT) for the grant SFRH/BPD/14554/2003. Marcia C. Neves thanks the University of Aveiro for a PhD grant. This work is supported by FCT, POCI and co-financed by FEDER (POCI/QUI/59615/2004).