Green and efficient deep eutectic solvent strategy for rapid aging of Castanopsis sclerophylla wood: a sustainable approach to restore ancient wooden architecture

The restoration of ancient wooden architectures demands sustainable strategies to produce antique-style wood that mimics naturally aged wood in both aesthetics and structural integrity. Traditional methods for artificial wood aging face challenges in efficiency, scalability, and environmental impact. This study proposed a green and rapid approach using a formic acid/guanidine hydrochloride deep eutectic solvent (DES) combined with potassium hydroxide (KOH) to accelerate the aging of Castanopsis sclerophylla , a key material in historical wooden structures. This dual-treatment process selectively degrades lignin (5.0 % reduction) and hemicellulose (13.4 % reduction) while preserving cellulose crystallinity, closely replicating natural aging mechanisms. The treated wood exhibits a characteristic concave-convex texture and darkened coloration akin to ancient wood, with minimal mechanical property loss (6.5 % decrease in bending strength, 8.4 % in modulus of elasticity). Crucially, this method operates under mild conditions (80–100 °C, 2–6 h), eliminating toxic reagents and energy-intensive steps. The work provides a scalable, eco-friendly solution for producing high-fidelity antique wood, addressing the urgent need for sustainable materials in cultural heritage preservation and antique-style construction.