Rebound behaviors of hydrophilic particle on gas bubble: effect of particle size and liquid properties

Abstract

AbstractBACKGROUNDThe interaction between particles and bubbles commonly occurs in catalysis, flotation and medical processes. Compared with the overwhelming amount of research dedicated to particle adhesion on gas bubbles, there is less on the rebound behaviors of hydrophilic particles on bubbles. Carrying out studies in order to understand the effect of particle size and liquid properties on rebound behaviors becomes an essential task.RESULTSThe rebound velocity and angle of a particle are small when a collision takes place near the top surface of a bubble. At the bubble top, gravity counteracts the upward rebound. Smaller rebound velocity is found for small particles due to inertia. The contact time between particle and bubble increases with an increase in particle size. The surface tension almost has no effect on the rebound velocity and angle of particles. By increasing liquid viscosity, the rebound velocity of the particles decreases and the contact time increases.CONCLUSIONSA hydrophilic particle cannot adhere on a gas bubble in pure water. However, at very large viscosity, adhesion takes places. In processes where longer contact time between hydrophilic particle and gas bubble is desirable, increasing liquid viscosity and particle size should be the choice, while efforts to change the surface tension are found to be unnecessary. Hydrophilic activated carbon particles have better dispersion in water and shorter contact time on bubble surfaces than hydrophobic N‐doped carbon particles. © 2021 Society of Chemical Industry (SCI).