Energy-efficient phytic acid-assisted chemo-thermal modification for valorization of bamboo residues into...

Industrial bamboo culm residues generated during harvesting and primary processing represent an abundant and renewable lignocellulosic resource with considerable potential for sustainable construction materials. However, their inherent hygroscopicity leads to severe dimensional instability under variable environmental conditions, limiting practical utilization. To overcome this limitation, this study investigates an energy-efficient phytic acid (PA)-assisted chemo-thermal strategy to regulate the hygroscopic behavior of industrial bamboo culm residues, aiming to promote cleaner production and bamboo valorization. Results showed that the volumetric swelling coefficient decreased from 2.96% in the untreated control to 1.28-2.31% after PA-assisted heat treatment, while the anti-swelling efficiency (ASE) ranged from 21.96% to 56.76%. The optimized condition achieved a volumetric swelling coefficient of 1.43% and an ASE of 51.69%, comparable to that of conventional high-temperature treatment, while reducing the treatment temperature by 20 °C and the processing time by 50%. Structural analysis indicated that phytic acid accelerated the degradation of hygroscopic polysaccharides, particularly hemicellulose, and promoted cell wall polymer rearrangement, accompanied by relative lignin enrichment. Meanwhile, spectroscopic evidence suggested possible phosphate-related interactions. These changes reduced hydroxyl accessibility and enhanced moisture resistance while preserving mechanical strength (MOR = 142.0 ± 6.2 MPa). This study provides an efficient and low-energy strategy for improving dimensional stability of industrial bamboo culm residues and supports the sustainable valorization of lignocellulosic biomass.