Stability of Colloidal Ferricoxychloride in the Presence of Inorganic Anions

Stability of zirconia sol in the presence of various inorganic electrolytes

“…The structure of the inner region of the electrical double layer (edl) for such systems is very often described by the site-binding model. 11 Most colloidal particles are electrically charged, e.g., most metal oxides have surface layers formed by/made of hydroxyl groups which are amphoteric and can become either positively or negatively charged, by proton association or proton dissociation, depending on the pH: 12 ≥Zr-OH + H +  ≥ZrOH 2 + , pH < pH pzc (1) ≥Zr-OH + OH - ≥Zr-O -+ H 2 O, pH > pH pzc (2) Reaction (1) is favored by a low pH, while reaction (2) occurs at a high pH. pH pzc represents the pH value at which the solid surface charge is equal to zero.…”

“…The interaction between a colloid and an electrolyte depends on the nature of the solid phase, especially on its surface composition, as well as on the type and concentration of ion species in the solution. 2 A fair amount of interest has also been shown in the stability of colloidal dispersions. [3][4][5][6][7][8][9][10] Charged colloidal particles lead to the formation of a layer of opposite charge in the fluid adjacent to a particle -the so-called diffuse electrical double layer -that partly screens the charge on the particle.…”

“…Whether or not a dispersion is stable depends on both the surface 1976 MARKOVIĆ, MILONJIĆ and LEOVAC electrostatic potential (dependent on dispersion pH) of the solid particles and the ion concentration in the solution. 2 Coagulation of a colloidal dispersion may be affected by numerous factors, such as dispersion aging, change in the amount of the dispersion phase, mechanical and light action, change in temperature, etc. However, the coagulation caused by the addition of an electrolyte into a sol is of the greatest theoretical and practical importance.…”