Quantitative evaluation of the structure-performance relationship of surface-coated superhydrophilic-underwater superoleophobic membrane for oil-water emulsion separation

Superhydrophilic-underwater superoleophobic membrane has been developed as a new type of oil-water separation membrane with high separation efficiency and wide applicability. Especially in the treatment of oil-water emulsions stabilized by surfactants, such membranes show unique advantages. Therefore, a novel superhydrophilic-underwater superoleophobic membrane based on surface coating technology was purposed, through combining mathematical models with experimental studies, the law of simultaneous enhancement of membrane flux and oil-water retention was revealed, and the mechanism of membrane structure parameters affecting the separation performance was systematically explored. By a complete metal polyphenol coordination network and surface coating of a metal polyphenol hydrogel containing graphene oxide, high retention (99.72%) and high flux (800.04   L/m²·h) were achieved, and the instability of the coating layer was improved (stable flux remained after continuous operation for 90   minutes). Through Origin correlation heat map and SPSS multiple linear regression, the influence of key structural parameters on membrane separation performance was determined. The results showed that: bulk porosity (BP) and roughness (Ra) are not only the key factors affecting the flux (R 2 =0.950), but also the key factors affecting the retention rate (R 2 =0.950). Therefore, this study provides a new theoretical basis for the design of superhydrophilic-underwater superoleophobic membrane, and provides theoretical and experimental basis for the selection of parameters through the establishment of mathematical models.