Premix membrane emulsification using flat microfiltration inorganic membranes with tailored structure and composition

Uniform oil-in-water emulsions were prepared using MCT (medium-chain fatty acid triglyceride, 10 wt%) as the oily dispersed phase and polysorbate 80 as the surfactant (1 wt%). The emulsification process was performed via premix membrane emulsification (PME) using 3 flat microfiltration ceramic membranes with different mean pore sizes (d(m)): borosilicate (symmetric, commercial, d(m): 1.39 mu m); SiOC (symmetric, manufactured, d(m): 1.76 mu m); and mullite (asymmetric, manufactured, d(m): 1.18 mu m). The droplets size and their distribution varied according to the membrane type and number of permeation cycles (up to a limit of 2 passes). All prepared emulsions presented a tendency to monomodal droplet distribution with span values in the range of 0.82-0.97. The coarse emulsion (premix) droplets were reduced from 6.30 to 4.50-2.17 mu m. The asymmetric membrane (mullite) exhibited the highest permeation fluxes at constant relative pressure for both water (43.1 x 10(-3) m(3) m(-2) s(-1)) and premix (Pass 1: 4.6 X 10(-3) m(3) m(-2) s(-1); Pass 2: 5.3 X 10(-3) m(3) m(-2) s(-1)), still maintaining satisfactory emulsification results.