Microfiltration Polymer Membranes for Separation of Oil Emulsions

Development of microfiltration membranes used to separate emulsions of oil and water is highlighted. Oil emulsion microfiltration parameters are studied and the change in particle size of emulsion dispersed phase within membrane filtrates is established. Commercial and composite microfiltration membranes with hydrophilic and hydrophobic surfaces are used. The average pore sizes of the commercial membranes are from 0.22 to 0.45 μm, and particle sizes of the dispersed phase of the oil emulsion are in the range from 525 to 554 nm. During microfiltration of 0.1% oil emulsion, high productivity of polymer membranes is established (800–12,000 dm3/m2 · h) with an operating pressure of 0.2 MPa. After oil emulsion separation using microfiltration membranes a reduction is observed in oil product concentration, the retention capacity of commercial membranes is 88–98%, for the nylon-polystyrene dynamic membrane it is more than 99%, and for NAC-1 composite membrane with a surface layer of cellulose acetate it is 67% (relatively low). After emulsion separation a reduction is observed in dispersed phase particle size in membrane filtrates by up to a factor of ten. A reduction in the absolute value of the ζ-potential of the emulsion in membrane filtrates compared with the initial value is also revealed.