凝胶网格沉淀法制备纳米二氧化硅

主要研究了凝胶网格沉淀法制备纳米二氧化硅的工艺条件,如:琼脂用量、HCl浓度、SiO32-离子浓度、反应物物质的量比(H /SiO32-)等因素对产物粒径的影响。实验确定制备纳米二氧化硅的最佳工艺条件为:琼脂质量分数为11.5%,盐酸浓度为0.6mol/L,硅酸钠浓度为0.4mol/L,最佳配比(SiO23-/H )为1:2.1。采用XRD、TG-DTA及透射电镜等测试手段对产物进行了表征。研究表明:采用凝胶网格沉淀法可制得平均粒径为40nm的二氧化硅粉体,凝胶网格沉淀法是一种制备纳米二氧化硅的简单的新方法,所得粉体粒径小,粒径分布窄,实验条件要求低,操作简便、易行,便于工业化生产。

Preparation of Nanocrystalline SiO2 by Gel-network Precipitation Method

The effect of various factors, such as agar dosage, hydrochloric acid concentration, SiO2-3 concentration and the reactants proportion (H /SiO2-3) on the diameter and morphology of SiO2 nanocrystalline, has been studied. The optimal preparation condition is agar dosage 11.5%, hydrochloric acid concentration 0.8mol/L, SiO2-3 concentration 0.4mol/L, and the reactants proportion (H /SiO2-3)2.1:1, respectively. The particle size and crystal type of the product were characterizde by XRD, TG-DTA and TEM. The results show that nano-SiO2 with the diameter of 40nm was achieved under the optimal condition. It was found that gel-network precipitation method is a new method to prepare nanometer SiO2. The product has smaller and narrow-distributing particle size. The gel-network precipitation method has advantage of convenient industrialization due to simple experimental equipment and easy operation to achieve the product.