Anisotropic bacterial cellulose/sodium alginate aerogels with enhanced radial/axial elasticity via multiscale pore...

The increasing severity of petroleum pollution has promoted the development of reusable and highly elastic aerogels. A biomass-based aerogel was constructed using a composite framework of bacterial cellulose (BC) and sodium alginate (SA), featuring hierarchically arranged channels, porous walls, and tube-bubble structures, achieved through directional freezing, tertiary butanol (TBA)-induced wall porosity, and sodium dodecyl sulfate (SDS) foaming. The continuous honeycomb-like aligned channels formed by directional freezing enhanced the mechanical performance of the aerogel and provided stable radial compressive recovery. Meanwhile, the TBA-induced porous walls and SDS-foamed tube-bubble structures endowed the aerogel with favorable axial compressive elasticity. After 1000 compression-release cycles, the plastic deformation in the radial and axial directions remained below 0.95% and 1.1%, respectively. The aerogel exhibited high absorption capacities for various oils and organic solvents, ranging from 63.58 to 134.75 g/g. After 20 absorption-squeezing cycles, the absorption capacity after radial and axial squeezing recovery remained above 95% of the initial values. This biomass-based hierarchical design provides a promising strategy for developing efficient, durable, and elastic materials for oil/water separation.