溶胶—凝胶法制备超滤Al_2O_3膜的研究I勃姆石溶胶的制备

A STUDY ON THE PREPARATION OF ULTRA-FILTRATED Al _ 2O_ 3 FILM BY SOL-GEL PROCESS

本文通过用异丙醇铝水解的溶胶—凝胶法制备了勃姆石溶胶。对其制备过程的主要影响因素—胶溶剂种类及其用量、水解温度及加水量、老化温度及老化时间等进行了研究，探索出了制备稳定、清澈的勃姆石溶胶（ 也称为铝溶胶） 的最佳条件，并对勃姆石溶胶的性质进行了探讨。证实勃姆石胶粒带正电荷，发现勃姆石溶胶稳定存在的ｐＨ 值为３ ．５ ～４ ．１ 。配性太强，溶胶粘度过大易胶凝；酸性太弱，得不到完全胶溶稳定的溶胶。

Boehmite sol (γ AlOOH sol) is prepared by sol-gel process with the aid of hydrolysis of alumina isopropyl alcoholate in this study.It also studies the main factors affecting its preparing process including the types and quantities of used peptizers,hydrolytic temperature,amount of added water,ageing temperature and ageing time and so on.The optimum conditions to prepare stable and clear boehmite sol are seeked,and its properties are also discussed in this paper.It has been demonstrated that the boehmite sol particles possess positive charges, and the stable existing range falls in the values of pH from 3.5～4.1. When the acidity is too strong,its collosol viscosity is too large and the sol becomes easily gelled.A complete peprized and stable sol cannot be gained when the acidity is too weak.There is not any apparent bounds between the transition of boehmite sols and gels.