Electrochemical parameters of Mg-Al-NO3LDH particles in different electrolytic solutions (LiCl, NaCl and KC1), including zeta potential, isoelectric point (Ph_(IEP)), permanent charge density (σ_P), and zero point of charge (pH_(ZPC)) have been measured by electrophoresis method and potentiometric titration. Effects of electrolyte, pH, and chemical composition on electric property of the positive sol were investigated. It has been found that the Ph_(IEP) decreases with the sequence of Li+, Na+, K+. Because of the permanent positive charge, the pH_(IEP) is not equal to the Ph_(ZPC); The values of bothσ_P and Ph_(ZPC) of Mg-Al-NO3IDH increase with the increase of the contents of Al3+ in the LDH samples, whereas the corresponding pHjEp decreases rather than the increase.

Key words: ELECTROLYTE, LITHIUM CHLORIDE, SODIUM CHLORIDE, POTASSIUM CHLORIDE, MAGNESIUM HYDROXIDE, ALUMINIUM HYDROXIDE, ELECTRIC POTENTIAL, ISOELECTRIC POINT, ELECTRICAL PROPERTIES