Effect of liquid surface tension on the detachment behavior of an air bubble and a glass bead

The effect of liquid surface tension on the detachment behavior of bubbles and different hydrophobic glass beads was investigated. By measuring the receding contact angle, induction time and detachment force, the mechanism of liquid surface tension on the detachment of bubbles and different hydrophobic glass beads was revealed. The results showed that when liquid surface tension was decreased from 72.86 ± 0.05 mN/m to 71.76 ± 0.04 mN/m, there were slight changes in receding contact angle, induction time and critical detachment force of different hydrophobic glass beads. This indicates that liquid diffusion and wetting on the glass bead surface were limited, and had a minimal effect on detachment behavior in a certain range of liquid surface tension. However, when the liquid surface tensions were 58.16 ± 0.12 mN/m and 41.74 ± 0.22 mN/m, the liquid diffusion and wetting on the different hydrophobic glass bead surfaces were enhanced. The receding contact angle and critical detachment force between bubbles and glass beads were decreased. It indicates that the extension of three-phase contact line (TPCL) between bubbles and different hydrophobic glass beads was hindered, thereby decreasing the stability of the aggregates. This research provides guidance on selecting optimal surface tension for separating different hydrophobic particles, therefore improving flotation performance.