Abstract:
Scalable and highly efficient bamboo whitening remains a great challenge. Herein, an effective bamboo whitening strategy is proposed based on photocatalyzed oxidation, which involves H2O2 infiltration and UV illumination. The as-prepared white bamboo well maintains the nature structure of natural bamboo and demonstrates high whiteness and superior mechanical properties. The absorbance value is significantly decreased to 3.5 and the transmittance is increased to 0.04 % in UV-visible wavelength range due to the removal of light-absorbing chromospheres of lignin, resulting in a high whiteness when the UV illumination time is 8 h. In addition, the white bamboo displays a high tensile strength of 30 MPa and a high flexural strength of 36 MPa due to the well-preserved lignin units (lignin preservation is about 89 %). XRD patterns and analysis show that photocatalyzed oxidation has no effect on the crystal parameters of cellulose. Compared with the traditional bamboo whitening technology, our photocatalyzed oxidation strategy demonstrates significant advantage including chemical and time conservation, high efficiency, environment friendliness, and mechanical robustness. This highly efficient and environmentally friendly photocatalyzed oxidation strategy for the fabrication of white bamboo may pave the way of bamboo-based energy-efficient structural materials for engineering application.
摘要:
可扩展和高效的竹子美白仍然是一个巨大的挑战。在这里,基于光催化氧化,提出了一种有效的竹子增白策略,其中涉及H2O2渗透和紫外线照射。所制备的白竹很好地保持了天然竹的自然结构,并表现出高白度和优越的机械性能。由于去除木质素的光吸收色球,在UV-可见光波长范围内,吸光度值显着降低至3.5,透射率提高至0.04%,当紫外线照射时间为8小时时,会产生很高的白度。此外,由于木质素单元保存良好(木质素保存约89%),白竹显示出30MPa的高拉伸强度和36MPa的高弯曲强度。XRD图谱和分析表明,光催化氧化对纤维素的晶体参数没有影响。与传统的竹子美白技术相比,我们的光催化氧化策略显示出显著的优势,包括化学和时间守恒,效率高,环境友好,和机械坚固性。这种高效环保的光催化氧化策略可以为竹基节能结构材料的工程应用铺平道路。