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化学学报
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化学学报 ›› 2004, Vol. 62 ›› Issue (4): 429-432. 上一篇    下一篇

研究简报

Zn-Al类水滑石零净电荷点及等电点研究

李丽芳1,2, 侯万国1, 戴肖南1, 刘春霞1   

  1. 1. 山东大学胶体与界面化学教育部重点实验室, 济南, 250100;
    2. 山东农业大学应用化学与材料科学学院, 泰安, 271018
  • 投稿日期:2003-05-19 修回日期:2003-10-10 发布日期:2014-01-26
  • 通讯作者: 侯万国,E-mail:wghou@sdu.edu.cn E-mail:wghou@sdu.edu.cn
  • 基金资助:
    国家自然科学基金(No.20273041)和教育部跨世纪人才基金资助项目.

Studies of the Point of Zero Net Charge and Isoelectric Point of Zn-Al Hydrotalcite-like Compounds

LI Li-Fang1,2, HOU Wan-Guo1, DAI Xiao-Nan1, LIU Chun-Xia1   

  1. 1. Key Laboratory of Colloid and Interface Chemistry, Shandong University, Jinan 250100;
    2. College of Applied Chemistry and Material Science, Shandong Agriculture University, Tai'an 271018
  • Received:2003-05-19 Revised:2003-10-10 Published:2014-01-26

PDF

744

被引次数

32

用非均相共沉淀法合成了系列Zn-Al类水滑石(HTlc)样品,研究发现Al/(Zn+Al)摩尔比(x)在0.31～0.52范围内可得到纯类水滑石相.用电势滴定法和显微电泳法分别测定了5个纯Zn-Al HTlc样品的零净电荷点(PZNC)和等电点(IEP),以考察结构电荷对PZNC和IEP的影响.研究发现随结构正电荷密度的增加,PZNC和IEP均降低;IEP高于PZNC,且随结构正电荷密度的降低,IEP与PZNC的差值也降低,表明IEP与PZNC的差异来自结构电荷的影响.结构正电荷对HTlc的IEP与PZNC相对大小的影响与高价阳离子特性吸附的影响一致.初步探讨了结构电荷对PZNC和IEP的影响机理.

关键词: 类水滑石, 层状双金属氢氧化物, 等电点, 零净电荷点, 电势滴定

A series of Zn-Al hydrotalcite-like compounds (HTlc) was synthesized by co-precipitation method. The structure and chemical composition of the samples were determined by X-ray powder diffraction and automatic X-ray fluorescent spectrometric analysis, respectively. The results showed that pure HTlc could be obtained in the range of 0 31≤x≤0 52[x=n(Al)/n<(Zn+Al)]. The point of zero net charge (PZNC) and isoelectric point (IEP) of pure Zn-Al HTlc were measured using potentiometric titration method and electrophoretic method, respectively. The results indicated that permanent charge led to shifts in the PZNC and IEP of HTlc samples, and this influence was just the same as that of the cations adsorption on HTlc samples. PZNC and IEP all decreased with x or permanent charge density increasing, and IEP values were higher than PZNC values for all samples. The difference value (IEP- PZNC) increased as x value increased, indicating that the difference came from the structure charge of HTlc samples.

Key words: hydrotalcite2like compound, layered double hydroxide, isoelectric point, the point of zero net charge, potentiometric titration