Synergistic reductive decolorization of waterlogged archaeological wood via a thiourea dioxide–amine borane system

Abstract

Waterlogged archeological wood (WAW) undergoes lignin oxidation in the presence of air, generating quinones and other conjugated chromophores that cause severe discoloration. As conventional reductants (e.g., Na 2 S 2 O 4 and NaBH 4 ) struggle to balance between decolorization performance and operational compatibility, a thiourea dioxide (TDO)–amine borane (AB) composite formulation was developed for WAW decolorization. A paper-based solid-phase model with a covalently linked o -quinone motif was constructed for quantitative evaluation. The performances of TDO, dimethylamine borane (DMAB), tert-butylamine borane (TBAB), and their combinations were evaluated on both model and WAW samples. The TDO–AB formulations outperformed single-component treatments in decolorization effect and rate. The optimal formulation (0.025 M TDO + 0.025 M DMAB) achieved decolorization ratios of 31.6% on hardwood and 23.2% on softwood, while maintaining near-neutral pH without extra buffer. This enhancement arises from synergistic generation of reductive species and complementary reduction pathways, providing an effective and operationally compatible approach for WAW decolorization.

The authors' abstract, as published at the source. npj Heritage Science, 2026 · DOI ↗