title: Preparation and characterization of TiO2/HZSM-11 zeolite for photodegradation of dichlorvos in aqueous solution.
abstract: The TiO2/HZSM-11 materials were synthesized using titanium isopropoxide as a TiO2 precursor and HZSM-11 a medium pore size zeolite with high thermal and chemical resistance as support. The amount of titanium isopropoxide was varied in order to obtain TiO2 concentrations of 3, 10, 20, 30 and 50 wt% in the final material. They were characterized by a series of complementary techniques: X-ray diffraction (XRD), ultraviolet-visible diffuse reflectance spectroscopy (DRS), transmittance Fourier transform infrared spectroscopy (FTIR) and scanning electron microscopy (SEM). The surface area of the TiO2/HZSM-11 samples decreased with the increment of TiO2 loading. As result of the increment of the calcination temperature from 450 to 800°C an increase in the size of the anatase crystals was observed. However, the X-ray diffraction patterns of the solids only presented the characteristic peaks of the anatase phase. The catalytic activity of the materials in the photodegradation of Dichlorvos (DDVP) depended on the TiO2 amount the thermal treatment temperature. The sample containing 30% TiO2 calcined at 450°C showed the best catalytic performance and it can be reused without noticeable activity loss during at least four cycles. The catalytic performance was similar to that of the P25 Degussa used as a reference but its separation, recovery and reuse was easier.
authors.affiliation: Grupo Zeolitas, CITeQ (Centro de Investigación y Tecnología Química), Facultad Córdoba, Universidad Tecnológica Nacional, Maestro López esq. Cruz Roja Argentina, Córdoba, Argentina.
authors.forename: Silvina
authors.initials: S
authors.lastname: Gomez
authors.forename: Candelaria Leal
authors.initials: CL
authors.lastname: Marchena
authors.forename: Luis
authors.initials: L
authors.lastname: Pizzio
authors.forename: Liliana
authors.initials: L
authors.lastname: Pierella
mesh_terms: D002384:Catalysis; D004006:Dichlorvos / Q000737:chemistry*; D010575:Pesticides / Q000737:chemistry*; D010782:Photolysis; D012996:Solutions; D013499:Surface Properties; D013696:Temperature; D014025:Titanium / Q000737:chemistry*; D017641:Zeolites / Q000737:chemistry*
chemical_list: D010575:Pesticides; D012996:Solutions; D017641:Zeolites; C009495:titanium dioxide; D004006:Dichlorvos; D014025:Titanium