以Si-Al凝胶、高岭土水热晶化合成多级孔道催化材料

Synthesis of Hierarchical Catalytic Materials From Si-Al Gel and Kaolin by Hydrothermal Crystallization

以硅铝凝胶为模板剂,在高岭土制浆过程中加入,经喷雾、焙烧后,在水热条件下晶化合成含有NaY分子筛和基质的多孔复合材料。采用X射线衍射法、N2静态吸附法对所合成的样品进行分析表征,考察了硅铝凝胶的加入量对NaY分子筛相对结晶度、n(SiO2)/n(Al2O3)以及复合材料孔道分布的影响。结果表明,随着硅铝凝胶加入量的增加,晶化产物在介孔范围内的孔容及比表面积均有较大幅度的提高,介孔分布也更为集中;当加入凝胶质量分数为10%时,介孔的孔容及比表面积达到最大,在20%时有所下降。在凝胶加入量为10%时,可以得到BET比表面积为480m2/g、总孔容为0.41mL/g、介孔孔容为0.22mL/g、介孔比表面积为98.9m2/g、结晶度为51.0%、n(SiO2)/n(Al2O3)为5.09的含有NaY分子筛和基质的多孔复合材料。

Composite materials containing NaY molecular sieve and matrix in the form of microspheres were synthesized by hydrothermal crystallization method with Si-Al gel as a template,which was added to the Kaolin slurry then spray-dried and calcined.The samples were characterized by X-ray diffraction,N2 adsorption-desorption.The effects of Si-Al gel amount added to Kaolin slurry on the crystallinity,the silica to alumina ratio and pore size distribution of synthesized catalytic materials were investigated.The results showed that after adding the gel,the pore volume and surface area in the mesoporous range of crystallized product were more substantial rise in referral,the pore size distribution was more narrowed.With added gel mass fraction of 10%,the mesoporous pore volume and surface area of crystallized product reached their largest value,and then declined at 20%.When added gel mass fraction was 10%,the hierarchical catalytic materials were obtained with BET surface area of 480 m2/g,total pore volume of 0.41 mL/g,mesopore pore volume of 0.22 mL/g,mesopore surface area of 98.9 m2/g,crystallinity of 51.0% and silica to alumina ratio of 5.09.