Closed-loop recyclable dynamic covalent crosslinked nanofibrous membranes for efficient oil/water separation

The effective separation of oil from oily wastewater is a critical endeavor due to the escalating global issue of oil pollution. Nanofibrous membranes have attracted significant attention in this realm, owing to their remarkable porosity and favorable surface-to-volume ratio. However, a prevailing concern lies in their unstable morphology at the micro/nano-scale, and the absence of viable recycling options upon reaching the end of their service life. For the first time, we present the development of closed-loop recyclable dynamic covalent crosslinked nanofibrous membranes (DCCNMs) with superior chemical stability, high porosity and hydrophobicity, rendering them highly efficient for oil/water separation. By combining dynamic covalent chemistry and membrane technology, the contaminated nanofibrous membranes can be closed-loop recycled by means of de-crosslinking to remove the accumulated contaminants. Subsequently, the de-crosslinked polymer can be electrospun and refabricated into new nanofibrous membranes via the thermally reversible Diels-Alder reaction. This study not only addresses the existing gaps in closed-loop recycling strategies for nanofibrous membranes but also provides insights and inspiration for the advancement of sustainable oil/water separation.