Charges, origin of surface

Oxide surfaces are high-energy surfaces that interact with water molecules becoming covered by a carpet of OH groups. The latter, in contact with aqueous solutions, behave as weak acids or weak bases, giving rise to dissociation that is the main origin of surface charging ... 

It is necessary to analyze first the origin of surface charge as suggested (or revealed ) by pH measurements (see also Figure 5.14). When an acidic (or basic ) carbon is immersed in water, its... 

The form of the Helmholtz free energy F depends on the type of the origin of surface charges on the interacting particles. The following two types of interaction, that is (i) interaction at constant surface charge density and (ii) interaction at constants surface potential are most frequently considered. We denote the free energy F for the constant surface potential case by F and that for the constant surface... 

Smit, W. and Stein, H.N., The origin of surface charges on the p-CaSiOj/dimethyl sulfoxide interface, J. Colloid Interf. Sci., 55, 208, 1976. 

FIGURE 7.2 Schematic representation of the origin of surface charge in nonaqueous media. (From Fowkes, F.M. and Pugh R.J., ACS Symposium Series, 240, 331, 1984. With permission.)... 

Phosphate ion exchange in soils In soils, phosphate and other ion exchange processes occur on the surfaces of the solid phases (clay minerals, organic matter, and mineral surfaces). Ion exchange reactions are important for maintaining an equilibrium between the solid phase and the solution (soil pore water). Thus, it is important that we understand the origin of surface charge of the solid phase. 

Electrostatic forces the electric double layer and the origin of surface charge... 

---