摘要
在25℃下以DPM—1型微电泳仪测定并研究了叶腊石(包括天然的和经加热焙烧的)的电泳淌度及ζ电势。在10^(-2)MNaCl中叶腊石粒子带负电荷,其电泳淌度随着测定时间的推延而变小,约在1小时之后,维持恒定。天然叶腊石的ζ电势与pH的关系,不论在10^(-2)M或10^(-3)MNaCl中均显示了其等电点为pH=2.7。当pH>2.7时,ζ电势为负值,且随pH的增加其绝对值加大,而pH<2.7时,ζ电势为正值,其值随pH的加大而减小。在同样的pH下,随着溶液中离子强度的增大,天然叶腊石的ζ电势就变小。但是对于经过加热焙烧的叶腊石的研究表明,其ζ电势只是随着pH的增大而增大,在实验已测定的pH范围内及其合理的外推下不存在等电点。本文对上述的实验结果,作了分析与讨论。
Using DPM-1 Microelectrophoretic meter,the mobility and ζ potential of s-uspensions of pyrophyllite (both natural and heated) in aqueous solutions at 25℃ have been measured.The influence of detecting time on mobility shows that the particle of pyrophyllite carries with negative charge in neutral medium, it decreases stably at beginning and about one hour later it keeps nearly constant. The relationship between ζ potential of natural pyrophyllite and pH indicates that the isoelectric point is pH= 2.7, if pH>2.7, ζ is negative and anincrease in ζ potential (absolute value) with increase in pH , while pH<2.7 , it is positive and the result is opposite. In addition, ζ potential of natural p-yrophyllite will decrease if ionic strength increases under the Same pH value. As for the heated pyrophyllite, it must the depen-dence ofζpotential on pH, be noted that is no isoelectric point in the pH measuring range,as pH rises the ζ potential(absolute value) increases only.
关键词
叶腊石
动电电势
等电点
电势测定
Zeta Potential, Pyrophyllite, Isoelectric point, Electrophoresis,Mobility
