Curcio Monique S, Oliveira Michel P, Waldman Walter R, Sánchez Benigno, Canela Maria Cristina
Laboratório de Ciências Químicas, UENF-CCT, Av. Alberto Lamego, 2000, Campos dos Goytacazes, RJ, CEP 28013-602, Brazil.
Environ Sci Pollut Res Int. 2015 Jan;22(2):800-9. doi: 10.1007/s11356-014-2683-4. Epub 2014 Mar 8.
Photocatalysts supported on polymers are not frequently used in heterogeneous photocatalysis because of problems such as wettability and stability that affect photocatalysis conditions. In this work, we used polypropylene as support for TiO2 sol-gel to evaluate its stability and efficiency under UV radiation. We also tested the effect of the thermo-pressing PP/TiO2 system on the photocatalytic efficiency and stability under UV radiation. The films were characterized by scanning electron microscopy (SEM), UV-Vis spectroscopy and X-ray diffraction (XRD). The SEM micrographs showed that the films of TiO2 sol-gel onto PP has approximately 1.0-μm thick and regular surface and the generation of polypropylene nanowires on hot-pressed samples. XRD showed the formation of TiO2 anatase on the surface of the films made by dip-coating. All photocatalysts were tested in decontaminating air-containing gaseous formaldehyde (70 ppmv) presenting degradation of the target compound to the limit of detection. The photocatalysts showed no deactivation during the entire period tested (30 h), and its reuse after washing showed better photocatalytic performance than on first use. The photocatalyst showed the best results were tested for 360 h with no observed deactivation. Aging studies showed that the film of TiO2 causes different effects on the photostability of composites, with stabilizing effect when exposed to most energetic UVC radiation (λmax = 254 nm) and degradative effects when exposed to UVA radiation (λmax = 365 nm).
由于存在诸如润湿性和稳定性等影响光催化条件的问题，负载在聚合物上的光催化剂在多相光催化中并不常用。在这项工作中，我们使用聚丙烯作为二氧化钛溶胶 - 凝胶的载体，以评估其在紫外线辐射下的稳定性和效率。我们还测试了热压PP/TiO₂体系对紫外线辐射下光催化效率和稳定性的影响。通过扫描电子显微镜（SEM）、紫外 - 可见光谱和X射线衍射（XRD）对薄膜进行了表征。SEM显微照片显示，负载在PP上的TiO₂溶胶 - 凝胶薄膜厚度约为1.0μm，表面规则，且热压样品上生成了聚丙烯纳米线。XRD表明，通过浸涂制备的薄膜表面形成了TiO₂锐钛矿。所有光催化剂都在净化含气态甲醛（70 ppmv）的空气中进行了测试，目标化合物降解至检测限。在整个测试期间（30小时），光催化剂没有失活，洗涤后再利用显示出比首次使用时更好的光催化性能。对表现出最佳结果的光催化剂进行了360小时测试，未观察到失活现象。老化研究表明，TiO₂薄膜对复合材料的光稳定性有不同影响，在暴露于能量更高的UVC辐射（λmax = 254 nm）时具有稳定作用，而在暴露于UVA辐射（λmax = 365 nm）时具有降解作用。
