Preparation of superhydrophilic membranes from discarded masks for efficient oil-water separation and anti-crude oil adhesion

To overcome the limitations of inefficiency and high operational costs associated with conventional oil–water separation technologies, this study introduces a novel membrane material inspired by the natural adhesive properties of mussels, derived sustainably from discarded face masks. A straightforward, eco-friendly one-step modification method employing gallic acid (GA) and polyethyleneimine (PEI) was adopted to fabricate a superhydrophilic coating on polypropylene (PP) membranes. The modified membrane exhibited exceptional wettability, characterized by a water contact angle (WCA) of 0° and an underwater oil contact angle (UWOCA) of 162°, along with remarkable flux performance of up to 43,935.11 L·m −2 ·h −1 for oil–water mixtures and 1,328.6 L·m −2 ·h −1 for emulsions. Performance tests further demonstrated significant enhancements in hydrophilicity, separation efficiency, fouling resistance, and reusability under demanding operational conditions. Environmentally benign, mechanically stable, and simple to implement, this membrane technology represents a promising approach for both sustainable recycling of waste face masks and advancement in high-performance separation technologies.