Structure and photocatalytic performance of TiO2/clay nanocomposites for the degradation of dimethachlor
Structure and photocatalytic performance of TiO2/clay nanocomposites for the degradation of dimethachlor
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DOI：
10.1016/j.apcatb.2006.12.011
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发表时间：
2007-05-11
影响因子：
22.1
通讯作者：
Albanis, T.
中科院分区：
文献类型：
--
作者：
Belessi, V.;Lambropoulou, D.;Albanis, T.
本研究通过在天然蒙脱石和合成膨润土表面分散二氧化钛来制备二氧化钛/粘土复合材料，以提高二氧化钛的吸附能力，从而提高其光催化作用。制备了六种不同负载量(15、30和55wt%)的TiO2光催化剂材料，并用X射线衍射仪、比表面积法和扫描电子显微镜对其进行了表征。该合成过程允许在沸石-二氧化钛样品中形成分层层，而在蒙脱石-二氧化钛复合材料的情况下，我们形成了更多的片状聚集。结果表明，随着二氧化钛含量的增加，蒙脱石-二氧化钛样品的孔体积和比表面积增大。相反，对于沸石-二氧化钛样品，随着二氧化钛含量的增加，比表面积和孔体积减小。以水中的氯乙酰苯胺除草剂(二甲草胺)为模型化合物，评价了纳米复合催化剂的光催化效率。根据Langmuir-HinShelwood模型，二甲草胺的一级降解符合准一级动力学。所有负载型催化剂都表现出良好的光降解效率，其单位质量二氧化钛的总脱除效率优于溶胶-凝胶法制备的裸二氧化钛。综上所述，该复合材料具有良好的沉降性能，是一种很有前途的去除有机水污染物的替代材料。(C)2007 Elsevier B.V.保留所有权利。
In the present study TiO2/Clay composites were synthesized by dispersion of TiO2 on the surfaces of a natural montmorillonite and a synthetic hectorite in order to increase the sorption ability of TiO2 and therefore its photocatalytic action. Six materials with different loading in TiO2 (15, 30 and 55 wt%) were prepared and characterized by several analytical techniques including XRD, BET and SEM analysis. The synthetic procedure allows the development of delaminated layers for hectorite-TiO2 samples, while in the case of montmorillonite-TiO2 composites we have the formation of a more lamellar-like aggregation. It was found that, the greater the percentage of TiO2, the greater the pore volume and the specific surface area of the montmorillonite-TiO2 samples. On the contrary, in the case of hectorite-TiO2 samples, as the content of TiO2 increases, the surface area and pore volume decreases. The photocatalytic efficiency of the nanocomposite catalysts was evaluated using a chloroacetanilide herbicide (dimethachlor) in water as model compound. The primary degradation of dimethachlor followed pseudo-first-order kinetics according to the Langmuir-Hinshelwood model. All supported catalysts exhibit good photodegradation efficiency and their overall removal efficiency per mass of TiO2 was better than that of bare TiO2 produced by the sol-gel method. In conclusion, together with their good sedimentation ability the composite materials could be considered as a promising alternative for the removal of organic water contaminants. (c) 2007 Elsevier B.V. All rights reserved.