Microstructure-performance relationships of hollow-fiber membranes with highly efficient separation of oil-in-water emulsions

The critical breakthrough pressure related to the membrane surface wettability and pore size is a key parameter determining membrane performance in particular applications, such as oil-water mixture separations. A series of hydrophilic polysulfone hollow-fiber membranes with different pore sizes were prepared and characterized to evaluate the separation performance of oil-in-water emulsions and to develop an optimum membrane for such emulsions. For the optimum membrane, the absolute value for the cosine of the surface oil droplet contact angle (0.72) was close to the ratio of the outer surface pore size to the oil droplet size (0.71); it was also similar to the absolute value of the cosine of the underwater oil contact angle on the polysulfone material (0.65). From the point of view of the surface wettability, theoretical calculations were performed to select a suitable membrane with the aim of reaching the maximum efficiency in practical oil-water mixture separation. (c) 2019 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2019, 136, 47615.