Emulsions prepared by two-stage ceramic membrane jet-flow emulsification

To solve the paradox between the flux and droplet size in conventional membrane emulsification, a process including a two-stage ceramic membrane emulsification under jet flow was proposed. An apparatus integrating slurry reactor and membrane emulsification was used in this investigation. In the first stage, a ZrO₂ ceramic membrane, with a nominal pore size of 0.16 μm, was used. The flux of the membrane was 150 L m^-2 h ^-1 at a pressure of 0.35 MPa and a temperature of 20°C, and the droplet size of the emulsion was 54.69 μm. To obtain monodispersed emulsions with a small droplet size, a second ceramic membrane jet-flow emulsification was used. An α-Al₂O₃ ceramic membrane with a nominal pore size of 1.5 μm was selected as the emulsification medium. The flux was attained at 454 L m^-2 h^-1 at a pressure of 0.2 MPa, and the monodispersed emulsion with droplet size (D₅₀) of 2.29 μm could be obtained. The effects of pressure, stirring speed, and emulsifier concentration on the second stage of the process were discussed in detail.