Optimization of Hydrogen Peroxide Bleaching for Translucent Bamboo (Gigantochloa robusta) Using Response Surface Methodology

Optimization of bleaching parameters is a critical step in regulating lignin content for the development of translucent bamboo materials.Accordingly, this study employed response surface methodology (RSM) to optimize hydrogen peroxide bleaching conditions for Mayan bamboo (Gigantochloa robusta), with lignin content as the primary response variable.The effects of bleaching temperature, hydrogen peroxide concentration, and reaction time were systematically evaluated using a quadratic RSM design.Lignin content was quantified using the Klason lignin method, and chemical and microstructural changes were characterized by Fourier transform infrared (FTIR) spectroscopy and scanning electron microscopy (SEM).The results showed that lignin removal exhibits a nonlinear dependence on the bleaching parameters, confirming the existence of an optimal bleaching window.The lowest experimentally measured lignin content was 1.50% under intermediate processing conditions.RSM optimization predicted an optimal condition of approximately 88°C, 9.85% H 2 O 2 , and 60 min, yielding a fitted lignin content of approximately 3.5% and a composite desirability of 0.806.FTIR analysis revealed attenuated lignin-associated aromatic bands alongside preserved polysaccharide functional groups, indicating selective delignification.Correspondingly, SEM observations revealed a progressive transformation from a dense, lignin-rich matrix to a porous, fibrillated cellulose network without severe fiber collapse.These findings highlight the importance of species-specific optimization and provide a quantitative and mechanistic basis for preparing bamboo substrates for the further development of translucent bio-based building materials.