中华医学超声杂志

应用化学 ›› 2011, Vol. 28 ›› Issue (12): 1448-1452.DOI: 10.3724/SP.J.1095.2011.00761

• 研究论文 • 上一篇    下一篇

气相SiO2在不同pH值介质中的分散特性

郑欧1,2*,万南红1,周明明2,周龙瑞2,陈体衔2,刘孝伟2   

  1. (1.福州大学化学化工学院化学系 福州 350108；2.超威电源有限公司 新能源技术研究院 长兴  313100)
  • 收稿日期:2010-12-27 修回日期:2011-03-17 出版日期:2011-12-10 发布日期:2011-12-10
  • 通讯作者: 郑欧,副教授; Tel:; Fax:0591-22866152; E-mail:zhengou@fzu.edu.cn; 研究方向：胶体与界面化学、电化学
  • 基金资助:
    福州大学科技发展基金(2008-XQ-09) 福州大学人才基金(XRC-0820)福州大学博士后科研启动基金资助项目

Effect of pH on the Dispersion Characteristics of Fumed Silica

ZHENG Ou1,2*, WAN Nanhong1, ZHOU  Mingming2, ZHOU  Longrui2,  CHEN Tixian2, LIU  Xiaowei2   

  1. (1.Department of Chemistry,College of Chemistry and Chemical Engineering,Fuzhou University,Fuzhou 350002;
    2.New Energy Technology Research Institute,Zhejiang Chaowei Power Co.,Ltd,Changxing 313100)
  • Received:2010-12-27 Revised:2011-03-17 Published:2011-12-10 Online:2011-12-10

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摘要：

以激光动态光散射法考察了气相SiO2在不同pH值的H2SO4和NaOH介质中的分散平均水化粒径与表面Zeta电位及二者间的关系。 Zeta电位数据表明，气相SiO2在水中分散的表面硅羟基的等电点(IEP)和滴定终点(TE)的pH值分别为pH(IEP)=2.09和pH(TE)=7.47，利用滴定终点pH (TE)给出了一种简单的气相SiO2表面Si-OH浓度的测定方法。 分散相粒径数据显示，在等电点和滴定终点之间，气相SiO2在水中的分散粒子的粒径能够稳定在230 nm附近；在H2SO4介质中，当pH＜pH(IEP)时，随着H2SO4浓度的增大，体系中的分散粒子发生聚结而使表观粒径增大；在NaOH介质中，当pH＞pH(TE)时，随着NaOH浓度的增大，分散相的表观水化粒径降低，表明NaOH的加入有利于气相SiO2的分散。

关键词: 气相SiO2, 激光动态光散射技术, Zeta电位, 硅羟基浓度

Abstract:

The effect of pH on the particle distribution and zeta potential of the fumed silica(SiO2) suspended in H2SO4 or NaOH aqueous solution and their relationship were investigated with laser dynamic light scattering(DSL). The experiment showed that the isoelectric point(IEP) and titration end(TE) of silanol were at pH(IEP)=2.09 and pH(TE)=7.47, respectively, and a simple method was given for the determination of Si-OH concentration on SiO2 particle surface based on pH(TE). The dispersed phase particle size measurement showed that between IEP and TE, the hydration radius of SiO2 was stabilized near 230 nm; in H2SO4 medium, when pH＜pH(IEP), the apparent hydration radius of SiO2 increased with the increased H2SO4 concentration due to the coalescence of dispersed SiO2 aggregates; in NaOH medium, when pH＞pH(TE), the SiO2 aggregates decomposed and the apparent size of the dispersed phase decreased with increasing the NaOH concentration, which showed that NaOH can promote the dispersion stability of fumed silica in aqueous.

Key words: Fumed silica, Laser dynamic light scattering, Zeta potential, Si-OH concentration

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