Highly efficient recovery of viscous oil through nondispersive solvent extraction using polydopamine modified PVDF Janus membrane

Viscous oil separation and its highly efficient recovery is a great challenge in oil/water separation applications. Membrane separation was considered as a prospective strategy for oil/water separation, but membrane contamination caused by the oil droplets restricted its applications significantly. We here propose a nondispersive solvent extraction strategy to efficiently recover viscous lubricant oil from emulsions via a polydopamine modified PVDF Janus membrane. The incorporated thin polydopamine layer facilitates the adsorption and diffusion of surfactant stabilized oil droplets through the membrane. We studied the influence of polydopamine coating time, the flow rate on both feed and extraction sides, the weight content of lubricant oil on the recovery of oil. The optimized membrane exhibited a 10 h accumulative flux (1595 g·m−2) for viscous lubricant oil in water emulsion, which was 70 % higher than the contrast PVDF membrane. The current study might significantly advance application of this novel method for highly efficient separation and recovery of viscous oils from oil/water mixtures.