Effect of the properties of oil, particles, and water on the production of Pickering emulsions

Oil-in-water Pickering emulsions were prepared using a standard mixing configuration. Emulsification experiments were performed in an unbaffled tank using an off-centered pitched-blade turbine. Regular and modified glass beads were used as,a stabilizer, and their size, concentration, and wettability effects were investigated as were oil viscosity and the properties of the aqueous phase (pH and salinity). Our findings highlighted the importance of the stabilization mechanism in the emulsification process, which is different from that of surfactant-based systems. The stabilization mechanism can be divided into four steps: (1) droplet formation by breakage, (2) particle/droplet approach and collision, (3) particle adsorption, and (4) formation of the particle network. Emulsification efficiency was mainly quantified by size distribution measurements using a Mastersizer 3000 (Malvern). Our results showed that droplet stabilization is closely related to particle/droplet approach, collision, and initial adsorption and that it is highly sensitive to oil viscosity and particle size and wettability, while the properties of the aqueous phase influence stabilization mainly through their effect on particle interactions (flocculation). The smallest droplets with the narrowest distribution were obtained with small particles, low Oil viscosities, and good oil/particle affinity. It was possible to modulate the effects of particle size and oil viscosity by increasing oil/particle affinity. We also showed that stabilization efficiency is dependent on the particle fraction. (C) 2015 The Institution of Chemical Engineers. Published by Elsevier B.V. All rights reserved.