Zeta Potential of Conductive Plates (I) Development of a Zeta Potential Determination Method

摘要

#zeta#-potentials of insulating plates, e.g., quartz and sapphire plates, have been measured by means of the plane interface technique. This technique involves determining the electro-osmotic flow velocity-depth profile of reference (polystyrene latex) particles inside a cell. The electro-osmotic velocity at the lower boundary of the cell, referring to the sample surface-solution interface, permits to calculate the #zeta#-potential of the sample. However, this method is inapplicable to electrically conductive plates such as metal, because its conductivity results in electrolysis of water and disturbs to electrically conductive plates such as metal, because its conductivity results in electrolysis of water and disturbs to establish the electro-osmotic velocity profile. It is proved to be efficient for measuring the #zeta#-potential of metallic plates by inserting an insulator between the cell and the conductive plate. The size of the spacer is 4 mm inside width and 45 #mu#m thick. The precision and accuracy of this method were proved to be + - 10 mV. This method is applicable to evaluate the adsorption between the aqueous ions and the aluminum alloy plates.