胶溶剂对TiO2成型载体性能的影响

以TiO2粉体为原料，采用挤条成型的方法制备了TiO2成型载体。考察了制备过程中胶溶剂类型柠檬酸含量、硝酸含量以及粘结剂／柠檬酸复配比等对TiO2成型载体性能的影响，并用抗压强度测试、比表面积（BET）、扫描电镜（SEM）等手段进行了表征。结果表明，胶溶剂的加入均可不同程度提高TiO2成型载体的抗压强度，但对载体的比表面积影响不显著。柠檬酸质量分数3％时载体的抗压强度最高；加入硝酸可提高载体的抗压强度外，还可使载体的孔径分布集中。采用适宜的粘结剂／＋7檬酸复配比，有利于制备抗压强度高、孔径分布集中、表面缺陷少的TiO2成型载体。在硝酸质量分数3％、m（粘结剂）／m（柠檬酸）为4：6，焙烧温度700。C的制备条件下，载体的抗压强度、比表面积和孔容可分别达125．8N／cm，48．6m^2／g和0．33cm^3g。

Effect of Peptizers on Properties of Formed TiO2 Supports

Formed TiO2 supports were prepared by extrusion process using TiO2 powder as raw material. The influence of the kinds of peptizers, the contents of citric acid, the contents of nitric acid, and the binder/citric acid mass ratios on properties of the formed TiO2 supports were investigated, and these supports were characterized by crushing strength test, BET and SEM methods. The results show that all the peptizers can improve the crushing strength of the formed TiO2 supports; however, peptizers have little effect on the surface area of the supports. The added citric acid can remarkably increase the crushing strength of the formed TiO2 supports, and the maximum value can be obtained when mass fraction of 3% citric acid is added. Addition of HNOa can increase the crushing strength and narrow the pore size distribution of the formed TiO2 supports. It is also found that the formed TiO2 supports with high crushing strength, narrow pore size distribution and little surface defects can be prepared using the suitable binder/citric acid mass ratio. Under the preparation conditions of nitric acid mass fraction of 3%, binder/citric acid mass ratio of 4 ： 6 and calcination temperature of 700 ℃, the crushing strength, surface area and pore volume of the formed TiO2 support can reach 125.8 N/cm, 48.6 m^2/g and 0.33 cm^3/g, respectively.