Optimizing membrane structure through interfacial instability of a two-component system to increase mechanical and separation performance

Abstract

The treatment of oily wastewater holds significant importance for both the environment and living organisms. Among various treatment methods, the design of separation membrane structures is a key focus for emulsion separation in oily wastewater. The preparation of bimodal fibers not only enhances the selectivity of the separation process but also leverages the advantage of high porosity inherent in electrospun fibers. In this work, bimodal fibers were successfully prepared by regulating the interfacial interaction between the two components, resulting in jet splitting due to the inhomogeneity and instability of the spinning precursor. In addition, it is found that the use of a surfactant and a zwitterion can achieve the same effect, which is conducive to the promotion and application of this strategy. Compared with a unimodal fiber, the bimodal fiber overcomes poor mechanical strength and fragility. In the field of emulsion separation, it also showed a higher separation efficiency, reaching 99.7%. Even if the fibers are separated for a long time without cleaning, the decrease in the permeation flux is less than that of unimodal fibers, and the efficiency is essentially unchanged. After cleaning, the flux can be completely recovered, proving that the bimodal fiber has an effective barrier against oil contamination.