Origins of surface charge
From Soft-Matter
Contents
Introduction
Origin of charge - Ionic solids
| Substance | PZC |
|---|---|
| Fluorapatite, Ca5(PO4)3(F, OH) | pH = 6 |
| Hydroxyapatite, Ca5(PO4)3(OH) | pH = 7 |
| Calcite, CaCO3 | pH = 9.5 |
| Fluorite, CaF2 | pCa = 3 |
| Barite (syntheitc), BaSO4 | pBa = 6.7 |
| Silver iodide, AgI | pAg = 5.6 |
| Silver chloride, AgCl | pAg = 4 |
| Silver sulphide, Ag2S | pAg = 10.2 |
Origin of charge for oxides
| Oxide | PZC | Oxide | PZC | Oxide | PZC |
| Ag2O | 11.2 | HgO | 7.3 | SnO2 | 5.6 |
| Al2O3 | 9.1 | La2O3 | 10.1 | Ta2O5 | 2.8 |
| BeO | 10.2 | MgO | 12.4 | ThO2 | 9.2 |
| CdO | 11.6 | MnO2 | 5.3 | TiO2 (rutile) | 5.7 |
| CeO2 | 8.1 | MoO3 | 2 | TiO2 (anatase) | 6.2 |
| CoO | 10.2 | Nb2O5 | 2.8 | V2O3 | 8.4 |
| Co3O4 | 7.4 | NiO | 10.2 | WO3 | 0.4 |
| Cr2O3 | 7.1 | PuO2 | 9 | Y2O3 | 8.9 |
| CuO | 9.3 | RuO2 | 5.3 | ZnO | 9.2 |
| Fe2O3 | 8.2 | Sb2O5 | 1.9 | ZrO2 | 7.6 |
| Fe3O4 | 6.6 | SiO2 | 2 | ||
Adsorption of ionic surfactants
Origins of surface charge of colloids
Most particles in an aqueous colloidal dispersion carry an electric charge There are many origins of this surface charge depending upon the nature of the particle and it's surrounding medium Consider the more important mechanisms
