Brownian diffusion of ultrafine particles to an air–water interface

Fluorescent core-plain shell silica particles of different sizes were synthesized in order to investigate the interaction of ultrafine particles with bubbles. The morphology, surface chemistry and rate of diffusion of these synthesized particles were characterized by various techniques. The collection efficiency of particles by bubbles was measured in single bubble flotation experiments. Results show that particle-bubble collection efficiency increased with decreasing particle size and increasing particle surface hydrophobicity. These results are interpreted by taking into account the influence of particle size and surface hydrophobicity on particle-bubble collision and attachment efficiencies.