title: Photocatalytic decolorization of methylene blue in the presence of TiO2/ZnS nanocomposites.
abstract: 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 20ppm methylene blue solution, at natural pH was achieved in less than 20min, nearly 70min faster than the TiO2 photoassisted process.
authors.affiliation: CCMM and Department of Chemistry and Biochemistry, University of Lisbon, Campo Grande, Ed. C8, 1749-016 Lisboa, Portugal.
authors.forename: A
authors.initials: A
authors.lastname: Franco
authors.forename: M C
authors.initials: MC
authors.lastname: Neves
authors.forename: M M L Ribeiro
authors.initials: MM
authors.lastname: Carrott
authors.forename: M H
authors.initials: MH
authors.lastname: Mendonça
authors.forename: M I
authors.initials: MI
authors.lastname: Pereira
authors.forename: O C
authors.initials: OC
authors.lastname: Monteiro
mesh_terms: D002384:Catalysis; D004396:Coloring Agents / Q000737:chemistry*; D006863:Hydrogen-Ion Concentration; D008751:Methylene Blue / Q000737:chemistry*; D008854:Microscopy, Electron; D053761:Nanocomposites / Q000737:chemistry* / Q000648:ultrastructure; D010777:Photochemistry; D013057:Spectrum Analysis; D013440:Sulfides / Q000737:chemistry*; D014025:Titanium / Q000737:chemistry*; D017967:Zinc Compounds / Q000737:chemistry*
chemical_list: D004396:Coloring Agents; D013440:Sulfides; D017967:Zinc Compounds; C009495:titanium dioxide; D014025:Titanium; C031238:zinc sulfide; D008751:Methylene Blue