In Situ Cellulose Removal from Wood: A Novel Strategy for Preparing Simulated 80,000-Year-Old Waterlogged Archaeological Wood

Waterlogged archaeological wood (WAW), characterized by extensive degradation of cellulose and hemicellulose with concomitant relative lignin enrichment, represents a vital yet vulnerable class of cultural heritage materials. Due to the scarcity of archaeological wood specimens, the preparation of simulated WAW is essential for the systematic development and rigorous evaluation of consolidation and conservation treatments. However, existing simulation methods cannot adequately replicate the characteristic composition of WAW—namely, preferential polysaccharide loss and relative lignin enrichment—within practical timescales. This study presents a novel in-situ strategy utilizing recoverable lithium bromide (LiBr) under precisely controlled thermal conditions to fabricate simulated WAW with tunable degradation levels. Under optimized conditions (40 wt % LiBr, 150 °C, 8 h), the treated wood achieved a maximum water content (MWC) of 779% (degradation grade IV). Comprehensive characterization via FTIR, XRD, TGA, and polarized light microscopy confirmed faithful replication of archaeological degradation, including lignin enrichment, cellulose amorphization, and reduced crystallinity (13.3%). Concentration-dependent investigations revealed distinct mechanisms, swelling-mediated degradation versus cellulose dissolution, offering versatile control over degradation kinetics. The LiBr solution can be recovered and recycled by evaporation and concentration, thereby reducing reagent consumption and waste generation. This recoverable LiBr approach establishes a reproducible and benchmarkable platform for developing conservation materials for wooden cultural heritage while demonstrating considerable potential for broader applications in heritage science and advanced materials engineering.