Zeta Potential

Information obtained

  • Surface charge of planar, powder and rock slice samples, as a function of solution pH, ionic strength and composition
  • Isoelectric point, pHpzc, the pH where net charge is zero
  • Adsorption studies of surface active components (surfactants)

Principle

In electrolytes, most surfaces have an excess of positive or negative charge that is compensated by ions in the electric double layer (EDL). Even hydrophobic surfaces have an apparent charge because of dissociation in the ordered water layer at the surface. The surface charge depends on the nature of the solid, the composition of electrolyte solution (concentration, pH) and the interactions of the ionic species with the surface, thus influencing the adsorption properties of the solid.

ZetaPotentialGraph
Variation of the Zeta-potential of single crystal of α-Al2O3 {0001} and powder of α-Al2O3 with pH of 1 mM NaCl solution.