ABSTRACT
In solutions, there are ions, which always interact with the surface, and are called the potential-determining ions. There are also ions, which do not interact with the surface, and are called the (no surfaceactive) indifferent ions. Intermediate between these extremes are ions, which interact in some special way with the surface and these are referred to as the specifically adsorbed ions. Ba2• and SOl· are the potential-determining ions for barite and H+, OH" for oxides. Ions such as K+, Na+, Cal· and N03• are the active-active indifferent ions for Fe20 3• These ions maintain the electroneutrality in solutions. Surface-active ions can adsorb specifically in the Stem layer. These include both surface-active inorganic and organic ions. The surface-active inorganic ions are, for example, multivalent cations and anions, which adsorb at the interface due to the local electrical interactions, or hydrolyzed metal ions which adsorb by solvation effects and chemisoption effects. The surface-active organic ions include flotation reagents, which can adsorb both electrostatically and through hydrocarbon chain association in the
Stem layer - they are the physisorbing ions, or chemically bond with surface sites and - they are the chemisorbing ions.
