Cyclic molecule aerogels: a robust cyclodextrin monolith with hierarchically porous structures for removal of micropollutants from water

Abstract

A series of robust cyclodextrin (CD) monoliths, cyclic molecule aerogels, were synthesized via supercritical drying of organogels formed by in situ catalyst-free cross-linking of CDs with soft and rigid isocyanates. The CD aerogels exhibit outstanding mechanical properties with high Young's modulus up to 166 MPa, and can be compressed up to 70% without any observable cracking, which is a significant achievement because CDs or CD polymers are normally powders and have extreme difficulty forming a mechanically strong monolith. Moreover, the aerogels have high BET surface areas (237 m² g⁻¹) and, unlike other aerogels, possess hierarchically porous structures including nano-cavities, micropores and mesopores for inclusion of organic molecules and polymers. Thus the CD aerogels are capable of removing various organic micropollutants from water, such as dyes, monomers and even polymeric surfactants.