Preservation of wood structure using stabilized alkaline bleaching agents: a novel and mild approach to enhance whitening for lignin-rich wood template

Abstract Preservation and enhancement of wood properties have become increasingly important due to the growing demand for sustainable materials in the construction and manufacturing industries. This study focuses on bleaching processes as an alternative to conventional delignification, aiming to retain a significant amount of lignin while achieving the desired whiteness of the wood template. In particular, stabilized alkaline hydrogen peroxide is investigated as a bleaching agent under mild conditions. The treatment preserves more than 90% of the native mass in both balsa and birch, ensuring that most of the wood’s structural components are maintained. This results in a high wood volume fraction, corresponding to reduced porosity and a structure closely resembling that of unbleached wood. Fourier Transform Infrared spectroscopy (FTIR) semi-quantitative analysis further confirms that the relative lignin content is retained, ranging between 70 and 80% depending on the species. Unlike conventional approaches that often degrade the wood structure and require long treatment times at high temperatures, the proposed process is performed at room temperature under mild conditions and completed in less than 2–4 h, thus reducing energy demand and avoiding harmful byproducts. Overall, this work provides a bleaching strategy that combines efficiency, structural integrity, and sustainability, offering bleached wood templates suitable for further characterization and advanced applications.