The effect of electrostatic phenomena on the cleaning of surfaces

The objective of this paper is to determine the nature of adsorption of different components by measuring the surface potential in order to reduce fouling and to improve cleaning. In the discussion of adsorption, electrostatic and van der Waals forces are of paramount importance. van der Waals forces are often responsible for the adherence of hydrophobic groups. Electrical forces should be considered, since stainless steel becomes electrically charged in contact with ionic liquids. The electrical charge of stainless steel pipes is described by the Galvani potential, measured by means of special electrodes. This potential is mainly influenced by the pH and the oxidizing power of cleaning solutions and by the kind of surface finish. It was found that electrically charged globular or nearly globular particles show a tendency to adsorb by electrical forces. In contrast, particles which can be distinguished in hydrophilic and hydrophobic regions are mostly adsorbed by their hydrophobic groups by means of van der Waals forces. According to these results it is possible to reduce fouling and to get a better idea of the effects of cleaning and disinfectant solutions.