The interaction of a bubble with a particle-laden interface in frother solutions

Abstract

Spherical glass particles of varying degrees of hydrophobicity were studied for their monolayer formation and compression behavior on an aqueous subphase containing different frothers at various concentrations. A Langmuir trough was modified to mimic the coalescence between two bubbles by forming a single bubble just below the particle layer. The change in the layer following the film failure between the bubble and the particle-laden particles was captured visually. The movement of particles and the behavior of the ripple formed during the coalescence were also investigated to characterize the interface oscillation under the effect of frothers. The results showed that the surface pressure isotherms of both hydrophobic particles were more sensitive to PPG 425 than 1-pentanol and MIBC and that a small increment in the concentration of PPG 425 in the subphase led to a significant increase in surface pressure. Both 1-pentanol and MIBC behaved like a dispersant in terms of interaction with the particle monolayer. The coalescence of bubbles caused the release of excess energy which was dissipated through the expansion and contraction of the newly formed interface. The speed of the waves (ripples) was found to reduce in the presence of the particle monolayer. While frother types did not have a significant effect on the speed of wave spreading, the increase in the frother concentration reduced the wave speed compared to water.