二次催化溶胶-凝胶法制备多孔硅胶微球

Preparation of SiO_2 Microspheres by Two-step Catalytic Sol-Gel Method

以四乙氧基硅烷(TEOS)为原料,N,N-二甲基甲酰氨(DMF)为模板,采用二次催化的溶胶凝胶法制得微米级多孔性硅胶微球.考察了一次催化水解缩聚过程中水量、乙醇量,二次催化反应过程中电解质浓度、搅拌速度对微球粒径的影响,并采用扫描电子显微镜(SEM)、激光粒度分布仪、比表面及孔径分析仪、显微镜图像颗粒分析系统进行表征.结果表明,制得硅胶微球球形规则且无团聚现象,平均粒径(D50)为8.9μm,粒径呈典型高斯分布,比表面积546.67m2/g,孔体积0.7142m3/g,孔径主要分布在2～8nm之间,分布范围窄;硅胶微球粒径大小随一次催化过程中水量、乙醇量及二次催化过程中电解质浓度增加而增大,随乳状液形成过程中搅拌速度加快而减小.

Micrometer SiO2 microspheres were prepared by two-step catalytic Sol-Gel method with tetraethoxysi-lane（TEOS） as starting material and N,N-Dimethylformamide（DMF） as template.The effects of some factors on the diameter and particle size distribution of the SiO2 microspheres were discussed,such as H2O quantity and etha-nol quantity during the first catalytic process,the electrolyte concentration and stirring speed during the secondary catalytic process.SiO2 microspheres were characterized by SEM,Zetasizer,BET measurements and micro-scope-particle image analysis system.Results show that SiO2 microspheres are mostly regular-ball with no particle agglomeration.The mean particle size（D50） is 8.9μm,and the particle size distribution follows typical Gaussian distribution.The specific surface area is 546.67m2/g,and pore volume is 0.7142m3/g,with a narrow pore size varied from 2nm to 8nm.Also the particle size increases with water quantity,ethanol quantity and NaCl concentration in-creaing,but decreases with stirring speed acceleration.