Increasing surface hydrophilicity with biopolymers: a combined single bubble collision, QCM-D and AFM study

Area of Science:

• Materials Science
• Surface Chemistry
• Colloid Science

Background:

• Naturally derived polysaccharides like guar gum show potential as eco-friendly flotation reagents.
• Understanding guar gum's interaction with hydrophobic surfaces is key to optimizing mineral separation processes.

Purpose of the Study:

• To investigate the effect of adsorbed guar gum on the collision kinetics between gas bubbles and a graphite surface.
• To determine how guar gum influences the stability of the thin liquid film at the bubble-surface interface.

Main Methods:

• Quartz crystal microbalance with dissipation and atomic force microscopy were used to study guar gum adsorption on graphite.
• High-speed camera imaging captured bubble-graphite collisions on modified surfaces with millisecond resolution.

Main Results:

• Guar gum formed a concentration-dependent network on the graphite surface.
• Adsorbed guar gum significantly increased film drainage time and altered bubble bouncing characteristics.
• At higher concentrations, guar gum prevented bubble attachment, while at lower concentrations, it enhanced bubble bouncing.

Conclusions:

• Adsorbed guar gum layers modulate bubble-surface interactions by affecting film drainage and bubble rebound.
• The observed changes in bubble dynamics correlate with film drainage time, offering a predictive measure for flotation efficiency.