Innovative approach for making cellulose aerogels via deep eutectic solvent and ionic liquid for thermal and acoustic insulation in buildings

Improving energy efficiency in the construction sector requires sustainable thermal insulators, as most commercial products are fossil-based. This study reports a green approach to fabricate cellulose II aerogels from date palm wood waste using recyclable, non-toxic solvents. Cellulose was extracted via a natural deep eutectic solvent of choline chloride and formic acid, bleached with hydrogen peroxide, and dissolved in a 70 wt% 1-ethyl-3-methylimidazolium acetate (EmimAc)/30 wt% dimethylformamide (DMF) co-solvent. Processing at 2–5 wt.% cellulose yielded aerogels with low thermal conductivity (0.038–0.074 W/m·K), low densities (55–85 kg/m³), high porosity (94.16–96.31 %), and thermal diffusivity of 0.269–1.398 mm²/s. Mechanical and acoustic tests demonstrated a compressive strength of 500 kPa at 50 % strain and a sound absorption coefficient of up to 0.97, respectively. Structural characterization by XRD, FTIR, SEM, and TGA confirmed cellulose crystallinity and stability. These results highlight the potential of date palm-derived cellulose aerogels as eco-friendly, efficient, and multifunctional insulation materials for sustainable construction applications.