Induction Time of Wetting Films Between Air Bubbles and Hydrophobic Particles in the Presence of Dodecyl Amine...

An attachment of a particle on a bubble is a very complex process due to the surface chemistry of bubbles and particles, and hence it is difficult to describe the bubble-particle attachment mechanism from first principles. This paper focuses on better understanding of the bubble-particle attachment mechanism by predicting induction time from first principles for the glass beads-dodecyl amine hydrochloride (DAH) system. The induction time for the bubble-particle attachment was determined using an optically based attachment timer. The zeta potentials of bubbles and glass particles were measured by the microelectrophoresis method. The contact angle between a bubble and a particle was obtained using atomic force microscopy. In these calculations, the overall disjoining pressure and the overall energy of bubble-particle interactions comprised a sum of the DLVO and non-DLVO contributions. The overall energy of interactions was used to determine the critical film thickness, while the overall disjoining pressure was employed to estimate the wetting film drainage time using the theoretical models. By comparing experimental data and theoretical models for drainage of wetting films, it was found that the attachment of glass particles to air bubbles in the presence of DAH is accelerated due to the mobility of the air-water interface (of the wetting films), which has incorrectly been assumed as rigid (fully immobile) in the classical Stefan-Reynolds theory.