不同酸催化剂对有机-钛柱撑蒙脱石复合材料光催化活性的影响

The effect of different acid hydrolysis catalysts on the photocatalytic activity of surfactants modified TiO_2 pillared montmorillonites

以钛酸丁酯为前驱体,分别采用醋酸和盐酸为溶胶-凝胶法制备TiO2溶胶的酸催化剂,将制备的溶胶分别加入经阳离子表面活性剂十六烷基三甲基溴化铵改性的浙江临安和内蒙古膨润土中,制备了有机-钛柱撑膨润土复合光催化剂,并对其进行XRD,SEM,BET表征。实验结果表明:钛阳离子经交换进入了膨润土层间,并以锐钛矿型的晶形存在,而且制备的复合光催化剂具有较好的层状结构,其比表面积均比相应的未经柱撑的膨润土的比表面积大。并且以甲基橙为目标污染物,考察了所制备的有机-钛柱撑膨润土复合光催化剂的吸附性能和光催化活性,发现两种方法所制备的复合光催化剂均具有较好的光催化活性。但是由于在醋酸介质中溶胶的水解速度较慢,可形成稳定均质的凝胶,因而形成的TiO2粒径相对较小,因此对于不同类型的膨润土,以醋酸为酸催化剂制备的复合光催化剂均比用盐酸为酸催化剂制备的复合光催化剂的催化活性好。

TiO2 pillared clays were prepared by sol-gel method at certain ratio of Ti（OC4 H9）4 to acetic acid and Ti （OC4 H9）4 to hydrochloric acid. The pillared clays were pre-modified by cation surfactant cetyltrimethyl ammonium bromide （CTMAB） before clays were pillared with sol solution. Scanning electron microscopy （SEM） and X-ray diffraction （XRD） were used to investigate the texture of prepared catalysts, and their BET surface areas were also measured. The results indicated that the pillared montmorillonites were well pillared by the Anatase TiO2 and the BET surface areas were by far larger than the orient one. And then the sorption and photocatalytic performance of prepared pillared clays catalysts were studied by using methyl orange as mode organic pollutant. The pillared montmorillonites prepared by different acid showed different sorption and photocatalytic property which was mainly resulted from the different ionization of the acid. Moreover, it is found that although the TiO2 pillared clay prepared by hydrochloric acid have higher adsorption efficiency for the mode organic pollutants than that prepared by acetic acid, the TiO2 pillared clay prepared by acetic acid have more excellent photocatalytic activity for the degradation of mode organic pollutants than the hydrochloric acid one.