Shape memory and underwater superelastic mof@cellulose aerogels for rapid and large-capacity adsorption of metal ions

Cellulose aerogels have been used in widespread areas, such as absorbents, thermal insulation material and medical material. Herein, we propose an effective strategy to fabricate elastic cellulose aerogels by combining cellulose nanofibers with polyvinyl alcohol (PVA) “glue”. The CA not only had a robust chemical-bond cross-link network, but also had a strong H-bond, which enhanced underwater mechanical properties. Moreover, the compressible CA provided a large number of nucleation sites for the growth of Metal–organic framework nanoparticles (ZIF-67 and ZIF-8) through interface self-assemble. The obtained aerogels with a low density of 9.8–11.2 mg cm⁻³ and highly porous of 99.4–99.5% possessed excellent elasticity both in air and underwater. The adsorption capacities of the MOF@CA for Pb²⁺ and Cu²⁺ are up to 123 mg g⁻¹ and 70.53 mg g⁻¹, respectively. The novel MOF@CA adsorbents with excellent mechanical properties display application prospects in the removal of heavy metals from wastewater.