Mechanically Robust, Thermally Stable, and Crosslinked Bacterial Cellulose Aerogels for Superior Oil Absorption

Frequent oil spills and industrial oily wastewater discharges necessitate the development of high-performance, recyclable oil-absorbing materials, as traditional options suffer from low adsorption capacity and poor reusability. To address these limitations, this study developed crosslinked bacterial cellulose (BC) aerogels using 1,2,3,4-butanetetracarboxylic acid (BTCA) and sodium hypophosphite (SHP) as crosslinking agents. The aerogels were fabricated via freeze-drying and brief thermal esterification. By systematically optimizing BTCA content, the 10% BTCA formulation achieved a dense 3D network without crystalline precipitation, exhibiting high porosity (99.8%), minimal shrinkage (5.9%), and reduced pore size (2.2 nm). Crosslinking preserved the cellulose I structure but reduced crystallinity, as confirmed by FTIR and XRD. Thermal stability improved significantly, with residual mass at 600°C increasing from 21.8% to 39.0%. The aerogel demonstrated superior compressive resilience and structural stability in water, with oil absorption capacities of 115.4 g/g for paraffin oil, 98 g/g for engine oil, and 96 g/g for edible oil. Recyclability tests showed 84% retention after 20 ethanol cycles. This work provides a scalable, eco-friendly strategy for robust aerogels with multifunctional oil-absorption capabilities.