Preparation and characterization of TiO₂/HZSM-11 zeolite for photodegradation of dichlorvos in aqueous solution

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• 作者：Silvina Gomez ; C ; elaria Leal Marchena ; Luis Pizzio ; Liliana Pierella
• 关键词：Dichlorvos ; Water treatment ; Photodegradation ; TiO2/Zeolite ; Characterization
• 刊名：Journal of Hazardous Materials
• 出版年：2013
• 出版时间：15 August, 2013
• 年：2013
• 卷：258-259
• 期：Complete
• 页码：19-26
• 全文大小：2976 K

文摘

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 ¡ãC 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 ¡ãC 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.