A note on the synergistic effect of surfactants and nanoparticles on rising bubble hydrodynamics

摘要

Various mixtures of surfactants and nanosilica particles were investigated to assess their influence on rising bubble hydrodynamics. For this purpose, local velocities of rising bubbles were measured experimentally. Also, the effects of concentration of three types of surface-modified silica nanoparticles on density, viscosity, and surface tension of surfactant solutions were determined. Experimental results revealed that the simultaneous presence of nanoparticles and surfactant molecules led to the decrease of local velocities of rising bubbles. The presence of nanoparticles in surfactant solutions leads to a more reduction of bubble local velocity. This could be caused by the formation of surfactant-nanoparticle complexes and their adsorption at the gas-liquid interface. However, the increase of concentration of nanoparticles from 0.02 to 0.04 %wt led to an increase in bubble local velocities. That effect may be related to adsorption of surfactants to nanoparticle-liquid interfaces i.e. low surface coverage of surfactant, may increase local surface tension and lead to increasing the mobility of bubble surface.