Particle Surface Hydrophobicity

Theoretical basis for estimation To describe bubble-particle attachment after interception mathematically it is necessary briefly to review the nature and magnitude of the forces acting across the various interfaces.

After the initial interception, the particle and bubble will be separated by a water film. The film will become thin because of the forces of attraction between particle and bubble. The rate of thinning is determined by the dissipation of the kinetic energy of the particle on impact, associated with a resultant of long-range London-van der Waals molecular attraction (dispersion forces), capillary forces generated by the distortion of the bubble surface during the impact, electrostatic interactions between the uncom-pensated surface charges on the solid and those in the adjacent water layer, and as has been shown by Xu and Yoon, an additional force of attraction which appears to exist between two hydrophobic surfaces.

If the film thins to a critical value, failure will occur that will result in a successful attachment event. Both the thinning process and the critical thickness of the film must clearly depend on the interaction energy of the particle-water interface.

For the van der Waals forces of attraction, a treatment of the dispersion energy between a single gaseous atom and a slab of infinite extent is outlined by Adamson as:

Solar Panel Basics

Solar Panel Basics

Global warming is a huge problem which will significantly affect every country in the world. Many people all over the world are trying to do whatever they can to help combat the effects of global warming. One of the ways that people can fight global warming is to reduce their dependence on non-renewable energy sources like oil and petroleum based products.

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