柠檬酸催化木质素基CQDs的制备及其应用  

Preparation and application of citric acid-catalyzed lignin-based carbon quantum dots

作　　者：李潇潇 邱玉娟 马晓军[1] 李冬娜[1] 于丽丽[1] LI Xiaoxiao;QIU Yujuan;MA Xiaojun;LI Dongna;YU Lili(School of Light Industry Science and Engineering,Tianjin University of Science and Technology,Tianjin 300222,China)

机构地区：[1]天津科技大学轻工科学与工程学院,天津300222

出　　处：《林业工程学报》2022年第5期120-127,共8页Journal of Forestry Engineering

基　　金：国家自然科学基金(31870564)。

摘　　要：农林废弃物作为碳前驱体合成生物质碳量子点(CQDs)已被广泛关注,但因CQDs荧光性能较差而限制了其应用。以废弃的酶解木质素(EHL)为前驱体、柠檬酸(CA)为催化剂,通过绿色的一步水热技术制备高荧光性能的木质素基CQDs,并利用CQDs的光致发光特性开发了一种新型的CQDs/聚乙烯醇(PVA)荧光纳米复合材料。探究了催化剂的用量、碳量子点的形貌、结构、荧光性能以及复合材料的荧光性、紫外线屏蔽能力和抗氧化性能。结果表明:柠檬酸催化改性能够有效提高木质素基CQDs(CA-EHL CQDs)的荧光强度和效率。经柠檬酸催化改性的木质素基CQDs表现出高度结晶化结构且平均粒径为2.4 nm,其荧光强度是EHL CQDs的6.1倍,荧光效率最高可达5.0%。红外光谱和能谱数据分析表明CA-EHL CQDs表面富含羟基和羧基官能团,具有优异的水溶性。此外,通过紫外可见光透过曲线和1,1-二苯基-2-三硝基苯肼(DPPH)自由基清除率研究发现,CQDs/PVA纳米复合材料具有优异的荧光性能、紫外线屏蔽能力和抗氧化能力。本研究提供了一种绿色、高效、简便的木质素CQDs的制备方法,并对其功能化应用进行了有效尝试。The synthesis of biomass carbon quantum dots(CQDs)from agricultural and forestry wastes as carbon precursors has attracted extensive attention,but its application has been limited by the poor fluorescence properties of CQDs.In this study,using waste enzymatically hydrolyzed lignin(EHL)as a precursor,citric acid(CA)was dispersed in lignin aqueous solution to prepare high-fluorescence lignin-based CQDs by a green one-step hydrothermal technology.The photoluminescence properties of CQDs were utilized to develop a novel CQDs/polyvinyl alcohol(PVA)fluorescent nanocomposite.The effect of citric acid dosage on the fluorescence properties of lignin-based CQDs,the morphology,particle size,structure,fluorescence properties of lignin-based CQDs,and the fluorescence,UV shielding ability and antioxidant properties of the composites were investigated.The results showed that the citric acid catalytic modification could effectively improve the fluorescence intensity and efficiency of lignin-based CQDs.This was because the citric acid could provide an acidic environment for the hydrothermal system and promote the hydrolysis and carbonization of enzymatically hydrolyzed lignin.The surface of the obtained lignin-based CQDs was doped with abundant oxygen elements,which led to the formation of more defect sites in the CQDs.The TEM data showed that the citric acid-catalyzed modified CQDs exhibited a highly crystalline structure with an average particle size of 2.4 nm,and the fluorescence intensity was 6.1 times higher than that of the citric acid-free lignin-based CQDs.The fluorescence efficiency was increased from 0.8%to 5.0%.The Fourier transform infrared spectroscopy(FT-IR)and X-ray photoelectron spectroscopy(XPS)data analysis indicated that the surface of citric acid-catalyzed modified CQDs was rich in hydroxyl and carboxyl functional groups and had excellent water solubility.The UV-vis absorption spectroscopy and fluorescence spectroscopy analysis showed that the optimal excitation wavelength of CQDs was 365 nm and the optimal em

关 键 词：酶解木质素 碳量子点 柠檬酸 紫外线屏蔽 抗氧化性 

分 类 号：TB34[一般工业技术—材料科学与工程]