Reconstruction and functionalization of aerogels by controlling mesoscopic nucleation to greatly enhance macroscopic performance

This work presents a strategy for the mesoscopic engineering of hierarchically structured sodium alginate (SA) aerogels to enhance the macroscopic performance. The strategy was implemented by meso-functionalizing and reorganizing SA aerogels via controlled heterogeneous nucleation, in which microcrystalline cellulose-manganese dioxide (MCC-MnO₂) nano-crystallites worked as template. Due to the short rod-like structure and abundant hydroxyl groups of MCC-MnO₂, the organized mesostructure of SA aerogels was reconstructed during the assembly of SA molecule chains, which gave rise to a significant enhancement in macroscopic performance of SA areogels. For instance, the functionalized and reconstructed MCC-MnO₂/SA aerogels acquired a more than 70% increase in mechanical strength with an excellent deformation recovery. Furthermore, an almost double enhancement of removal capacity for metal ions (i.e., Cu²⁺ and Pb²⁺) and organic dyes (i.e., congo red and methylene blue) was obtained for MnO₂/SA aerogels, with an 87% repossession of the pollutants removal performance after 5 operation cycles.