Surface and electrokinetic properties of clays and other mineral particles, untreated and treated with organic or inorganic cations

The apolar (Lifshitz van der Waals) component (gamma(LW)) and the polar [electron-acceptor (gamma(+)) and electron-donor (gamma(-))] parameters of the surface tension of more than sixty different clay and other mineral particles or surfaces have been measured, as well as their zeta-potentials. It is essentially the gamma(-) parameter that determines the hydrophobic (gamma(-) < 28 mJ/m(2)) or hydrophilicy (gamma(-) > 28 mJ/m(2)) character of the mineral surface. The surface properties were measured for twelve ion exchanged smectites, as a function of substitution with various alkali and alkalin earth cations. The hydrophobizing influence of exchanged organic cations on the surface properties of a number of clay particles is also determined. Finally, the hydrophobizing influence of plurivalent cations is demonstrated with Ca2+ and La3+ for three different negatively charged mineral particles.