Deep eutectic solvent–derived microfibrillated cellulose from wood and agro-residues: Functionalization, energy-efficient production, and properties

Acidic deep eutectic solvent (DES) composed of choline chloride and lactic acid was investigated as a pulping and activation medium for producing functional microfibrillated cellulose (MFC) from wood and agro-residue biomass. Pine and hemp were selected to evaluate DES-assisted fiber activation, fibrillation efficiency, and material properties. DES processing induced fiber swelling and surface functionalization, reducing cell wall recalcitrance and enhancing fiber accessibility during mechanical refining. Compared with kraft-processed fibers, DES-derived fibers exhibited shorter fiber lengths, increased cell wall thickness, and higher fines content, enabling high-solids MFC production with substantially lower energy input. Hemp-derived MFC achieved a ∼ 90% fines at ∼430 kWh/t, representing >90% lower specific fibrillation energy than kraft-derived MFC requiring >5000 kWh/t for comparable fibrillation. Multiscale characterization revealed progressive fibrillar development and spatial distribution of residual lignin across DES-derived MFC surfaces. Under a prospective, literature-informed assumption of 94% overall DES recovery, techno-economic analysis estimated a minimum selling price of ∼ $1680/OD ton, indicating potential economic competitiveness with conventional MFC production. Overall, DES processing provides a promising high-solids, energy-efficient pathway for producing functional MFC from diverse lignocellulosic feedstocks, with potential applications in sustainable packaging, barrier coatings, rheology modification, and bio-based composites.