Engineered PEI-WS2 nanocomposite membranes for highly efficient pervaporation of water/isopropanol mixture

In this study, we present a novel approach to enhance pervaporation (PV) separation processes by addressing the challenge of membrane swelling due to organic aqueous solutions in polyelectrolyte composite systems. By integrating tungsten disulfide (WS2) and polyethyleneimine (PEI) into the membrane matrix, we synthesized a series of polyelectrolyte complex composite membranes on a modified polyacrylonitrile substrate. The unique interplay of WS2′s van der Waals forces and PEI's cationic attributes imparts enhanced structural stability and swelling resistance, culminating in a significant elevation of separation efficiency. The morphological and physicochemical properties of the membranes were meticulously characterized through scanning electron microscopy, atomic force microscopy, water contact angle measurements, and attenuated total reflection fourier transform infrared spectroscopy. In our pervaporation experiments, these membranes exhibited exceptional proficiency, separating a 70 wt% isopropyl alcohol aqueous solution under ambient conditions (25 °C, pH 7) with a fine-tuned PEI-WS2 ratio and concentration. The membranes achieved a permeation flux of 1380.86 g·m−2·h−1 and delivered a permeate with a water concentration of 99.71 wt%, underscoring their suitability for high-purity separations. Moreover, the membranes displayed consistent performance over extended operational periods, underscoring their robustness and durability. These results not only reinforce the potential of these membranes for industrial-scale separation tasks but also set the stage for further exploration into polyelectrolyte complex composites within the field of membrane science.