Engineering aramid nanofibers into robust macroscopic aerogel spheres for water purification

Aerogels are being developed for efficient removal of contaminants from water due to their high specific surface area and versatile surface chemistry. However, the formation of robust and chemical resistant aerogels is still challenging for practical implementation. Herein, the aramid nanofiber aerogel microspheres (ANFAMs) with dense skin and porous inner structures were fabricated on a large scale via the wet-spinning technique. The robust ANFAMs exhibit the ability to remove organic dye molecules with high efficiency in dynamic and harsh chemical environment. The visual study of weak interactions including electrostatic interactions, π-π interactions, and hydrogen bonding were revealed based on independent gradient model analysis. Moreover, one-step thermoinduced crosslinking enables the ANFAMs with superelasticity, which can maintain spherical after 500 compress-release cycles at 50% strain. The aerogel microspheres show excellent adsorption of various organic solvents with good reusability, paving the way to renewable adsorption for organic liquids from water. Therefore, this work provides a scalable and cost-effective production of robust aerogel microspheres toward the removal of the multiple water pollutants, and will guide future exploration on customizing high-performance enviromental remediation materials based on aramid nanofiber-based aerogels.