Removal of colloidal particles from quartz collector surfaces as stimulated by the passage of liquid-air interfaces

Micron-sized particles adhering to collector surfaces can be detached by passing a liquid-air interface over the adhering particles. Theoretically, the efficiency of particle detachment depends on the interface velocity, the liquid surface tension, the viscosity, and the particle-substratum interaction forces. In this study we perfuse an air bubble through a parallel-plate flow chamber to study detachment of polystyrene particles from a quartz collector surface, at different interface velocities and liquid surface tensions and upon multiple air bubble passages. A linear relation was found between particle removal and the liquid-air interface velocity, with negligible removal at elevated velocities. Linear relations were also found between particle removal and the liquid-air surface tensions, with different slopes for different air bubble velocities. Particle removal could be increased by the passage of multiple air bubbles. In summary, this study shows that liquid-air interfaces can be employed to detach micron-sized particles from collector surfaces. The detachment process can be optimized by adjusting the air bubble velocities, the surface tensions, and the number of bubbles applied.