Zn-Al类水滑石零净电荷点及等电点研究  

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

作　　者：李丽芳[1] 侯万国[1] 戴肖南[1] 刘春霞[1] 

机构地区：[1]山东大学胶体与界面化学教育部重点实验室

出　　处：《化学学报》2004年第4期429-432,共4页Acta Chimica Sinica

基　　金：国家自然科学基金 (No.2 0 2 730 4 1 );教育部跨世纪人才基金资助项目

摘　　要：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 3 1～ 0 5 2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 AlHTlc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 .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.

关 键 词：锌-铝类水滑石 零净电荷点 等电点 非均相共沉淀法 结构电荷 胶体颗粒 电势滴定 层状双金属氢氧化物 

分 类 号：O641[理学—物理化学]