This paper examines a mathematical model of the overall removal rate of particles during dissolved air flotation. It is shown that the particle capture efficiency for an isolated bubble–particle interaction can be calculated directly using a mathematical model provided the physicochemical properties of the bubble and particle are known. The mathematical model incorporates the exact hydrodynamics for an isolated bubble–particle interaction, including the influences of van der Waals forces and electrostatic forces. The mathematical model is used to determine how the overall flotation rate depends on bubble and particle size and on interparticle forces. It is shown that, if complete particle charge neutralisation can be achieved, then the overall rate of flotation can be enhanced by decreasing bubble sizes while increasing floc sizes.