Optimal utilization of waste wool: Preparation of bionic moisture-absorbing keratin membrane with hierarchical porous structure to harvest atmospheric moisture

Abstract

In addressing the challenge of water scarcity, solar-assisted atmospheric water harvesting (SAWH) has emerged as a promising strategy. Here, we have designed a hierarchical regenerated wool keratin membrane (LiCl@CNMC) that mimics the natural Murray network. Carbon nano tube, serving as solar absorbers, are uniformly deposited on the hierarchical keratin membrane. Hygroscopic salt LiCl is impregnated into the keratin membrane to achieve exceptional water uptake capacity. Under simulated sunlight exposure, the surface temperature can reach 83.5 °C. Furthermore, the LiCl@CNMC membrane exhibits outstanding water absorption (0.79–2.67 g g−1) and desorption performance at 30–80 % RH. The bionic water-collecting membrane can carry out 12 adsorption–desorption cycles every day under outdoor conditions, and yielding 11.92 g g−1 day−1 of clean water. The design of regenerated keratin membrane not only provides a direct way for the regeneration and utilization of keratin materials, but also provides valuable guidance and inspiration for the preparation and application of natural polymers found.