A green Fenton-like route to simultaneous bleaching and surface functionalization of bamboo at room temperature

Conventional bamboo bleaching relies on energy-intensive thermal processes and hazardous chlorine-based chemicals, posing significant environmental challenges. Herein, we report a green and sustainable strategy employing a Fenton-like reaction with low-concentration H₂O₂ activated by an Fe²⁺/Fe³⁺ redox cycle at ambient temperature. This approach achieves efficient surface whitening through hydroxyl radical-mediated selective degradation of lignin chromophores. Critically, it concurrently enables surface functionalization via introduction of polar oxygen-containing groups, as confirmed by FTIR and XPS analyses. This dual functionality substantially enhances photostability, reducing the color change (ΔE*) after accelerated aging by over 50% compared to untreated bamboo. Notably, under the optimized condition of 10% H₂O₂, the bending strength showed a non-significant change (from 106.7 MPa to 104.7 MPa, p > 0.05), quantitatively demonstrating that this mild oxidative system preserves the structural integrity and load-bearing capacity of bamboo. Microscopic and porosimetry analyses reveal increased surface roughness and restored porosity, facilitating subsequent processing. Density functional theory calculations elucidate the preferential reactivity of hydroxyl radicals with quinoid lignin units at the molecular level, corroborating experimental observations. From a cleaner production perspective, this process reduces energy consumption by approximately 0.6 kWh per kg of bamboo, eliminates toxic chlorinated reagents entirely, and enables facile wastewater treatment via iron precipitation through pH adjustment. This work establishes a versatile room-temperature platform not only for eco-friendly bamboo bleaching but also for the sustainable manufacturing of high-value functional bamboo materials.