Reusable and Recyclable Superhydrophilic Electrospun Nanofibrous Membranes with In Situ Co-cross-linked Polymer-Chitin Nanowhisker Network for Robust Oil-in-Water Emulsion Separation

The structural stability and mechanical strength of hydrophilic polymer nanofiber (NF) membranes are relatively low, because of the creep effect of polymer chain when swelling in water for a long time, which lead to a poor reusability in the fields of water treatment. In this work, we demonstrated a facile and green strategy for preparing eco-friendly hydrophilic nanofibrous membranes with excellent reusability and recyclability that could separate oil-in-water emulsion in practical conditions by using bio-based chitin nanowhiskers (ChNWs) as reinforcement and "co-crosslinking hub" for hydrophilic nanofiber matrix. The as-prepared membranes exhibited very good separation performance, with a separation flux of 1100-1300 L m(-2) h(-1) and a separation efficiency of > 99.5%. The reusability and recyclability of the membranes were evaluated and had proved to be robust enough to effectively separate emulsions after recycling at least 5 times. Moreover, the NF membranes were capable of effectively separating oil-in-water emulsions not only for a wide range of pH but also under hypersaline conditions. This work, as well as co-cross-linked strategies, enrich the exploration of superhydrophilic nanofibrous membranes for its significant potential in the field of oil spills and industrial oily wastewater treatments.