Sequential separation of oil-in-water emulsions using integrated hydrophilic and Janus membrane modules

Membrane technologies are extensively employed for the separation of surfactant-stabilized oil/water emulsions due to their high efficiency and selectivity. Either membrane filtration or demulsification experiences performance reduction due to the monotonous increase or decrease in emulsion concentration over time. In this study, we have developed a dual-membrane module that integrates a hydrophilic hollow fiber membrane module with a Janus hollow fiber membrane module. This synergistic approach effectively overcomes the limitations of individual filtration and demulsification processes by dynamically adjusting emulsion concentration within the system. Compared to single-membrane modules, the recoveries of both water and oil increased by 27 % and 280 %, respectively. Additionally, the water content in the permeate oil is less than 0.03 %, and the total organic carbon in the permeate water is less than 12 ppm. Furthermore, this design allows for the concurrent recovery of oil and water from emulsions, offering a promising approach to achieving zero liquid discharge.