Ordered hollow nanofiber aerogel with revivability for efficient oil absorption

Efficient, convenient, economical and environmentally friendly materials have always been the first choice for solving environmental problems. In this work, stable carbonized and ordered hollow nanofiber aerogels were obtained under the action of directional freezing and calcination. The benzoxazine monomer (BA) in the nanofiber was polymerized in situ under the action of high temperature to crosslink the nanofibers, thereby further stabilizing the aerogel structure. The plastic deformation of the carbonized aerogel after oil absorption with 100 cycles of compression was 30%. The carbonized hollow nanofiber aerogels were superhydrophobic and oleophilic, which allowed selective absorption of oil upon contact with oily wastewater. As a similar density, the oil absorption performance of the hollow nanofiber aerogels was higher than that of the normal nanofiber aerogels, implying high efficiency of the hollow nanofiber aerogels. After compression, the dry sample could recover its shape in oil, indicating the resilience of the hollow nanofiber aerogel. Moreover, the cycle absorption experiment illustrated that low-toxicity ethanol could remove most of the oil adsorbed in the aerogels, and ensure stable performance during recycling. After five cycles, the hollow nanofiber aerogel still retained its the original shape without fiber falling off, reducing the secondary pollution to the environment. The present study provides a strategy for the design and fabrication of ordered hollow nanofiber aerogels for wastewater treatment and other potential applications.