Effects of Electrolytes on the Electrokinetic Properties of Pumice Suspensions

Zeta potential values of particles and their sign are very important in many applications. In this study, the zeta potential values of pumice were obtained in the presence of various monovalent (LiCl, NaCl, KCl, NaClO4, and NaNO3), divalent (MgCl2, CaCl2, SrCl2, BaCl2, CuCl2, MnCl2, NiCl2, Na2CO3, and Na2SO4) and trivalent (AlCl3 and Na3PO4) salts. The zeta potential measurements were performed as a function of pumice concentration, pH, ionic species and electrolyte concentration by electrophoresis technique. The pH profiles of pumice/water systems at different pH values were obtained to determine the stability of suspension pH. The results showed that the zeta potential values of pumice in water did not change significantly with pumice concentration, while they changed mostly with pH. The isoelectric point of pumice was at pH 2.70. It was found that monovalent cations and mono-, di-, and tri-valent anions were indifferent electrolytes for pumice particles, on the other hand, di- and tri-valent cations were potential determining cations for them.