Zeta potential of air bubbles conditioned with typical froth flotation reagents

• The zeta potential (ζ) of air bubbles with flotation reagents is characterized.
• A novel setup and method for estimating the electrophoretic velocity is presented.
• Collectors strongly affect ζ but by contrast, frothers affect ζ only slightly.
• The pH affects the microbubble diameter, decreasing under acidic or basic conditions.

The effect of chemical flotation reagents on the zeta potential (ζ) of particles is well known, but their effect on bubbles is practically unknown. This study characterizes the ζ of air bubbles conditioned with typical froth flotation reagents and presents a novel experimental setup and method for estimating the electrophoretic velocity. It was observed that collectors strongly affect ζ in the following order from more to less anionic: xanthate, dithiophosphinate, deionized water, mercaptobenzothiazole and dodecylamine. By contrast, frothers affect ζ only slightly. In this study, it was also observed that pH affects the microbubble diameter and that under acidic or basic conditions, the bubble diameter decreases.