The role of hydrophobicity in dissolved air flotation

The dissolved air flotation of quartz particles and flocs has been studied to determine the role of the degree of hydrophobicity on the efficiency of the process. Stability, electrokinetic and adsorption data were correlated with batch dissolved air flotation tests using suitable collectors and flocculants. The presence of sufficiently hydrophobic material was found to be the critical factor controlling flotation response. Maximum flotation recovery coincided with suspension destabilization but the flotation of dispersed, hydrophobic particles was possible. It was concluded that little difference exists between the mechanisms of dispersed and dissolved air flotation in that without hydrophobicity stable bubble-particle attachments cannot form.