Abstract:

TiO₂/attapulgite nanocomposites were synthesized by the sol-gel method and supercritical fluid drying (SCFD) method using attapulgite as support and the aqueous solution of TiCl₄ as raw material. The composition, morphological properties and catalytic performance of catalysts were characterized by X-ray diffraction (XRD), scanning electron microscopy (SEM), transmission electron microscopy (TEM), X-ray photoelectron spectroscopy(XPS), and nitrogen adsorption-desorption measurements. The results show that there are no phase transformation from anatase to rutile about samples, the specific surface area of materials was increased. The adsorption property of attapulgite is excellent, the quantity of active adsorption sites on the surface of the materials were increased. TiO₂ calcined at different temperatures are all anatase, they have smaller particle size and short clavite structure. The photoactivity of the samples under UV light was evaluated by photocatalytic degradation of methylene blue in aqueous solution. The maximum photodegradation rate was obtained in the samples calcined at 400℃, it can reach 98.4% under the irradiation of ultraviolet light for 3 h.

Key words: attapulgite, TiO₂, SCFD, catalysis, nanomaterials, waste water

摘要：

以凹凸棒为载体，四氯化钛为钛源，通过溶胶-凝胶法结合超临界干燥法制备TiO₂/凹凸棒复合光催化材料。采用XRD、SEM、TEM、BET、XPS等方法对材料的结构、形貌及催化性能进行表征。研究结果表明：超临界干燥可增大复合材料的比表面积，抑制TiO₂发生晶型转变。凹凸棒吸附特性良好，增加了材料表面的活性位点，显著提高催化剂的光催化活性。不同煅烧温度下的TiO₂均为锐钛矿型，粒径约为20 nm，呈不规则短棒状，成功负载于凹凸棒上。在400℃煅烧2 h条件下，催化剂3 h后对亚甲基蓝的降解率可达98.4%。

关键词: 凹凸棒, TiO₂, 超临界干燥, 催化, 纳米材料, 废水