Raza Mohsin, Husain Arafat, Jawaid Mohammad, Inayat Abrar, Greish Yaser E, Meraj Aatikah, Abu-Jdayil Basim
Chemical and Petroleum Engineering Department, College of Engineering, United Arab Emirates University, 15551 Al Ain, United Arab Emirates; Research Institute of Science and Engineering, Biomass and Bioenergy RG, University of Sharjah, 27272 Sharjah, United Arab Emirates.
Chemical and Petroleum Engineering Department, College of Engineering, United Arab Emirates University, 15551 Al Ain, United Arab Emirates.
Int J Biol Macromol. 2025 Sep;321(Pt 4):146497. doi: 10.1016/j.ijbiomac.2025.146497. Epub 2025 Aug 5.
Lignin, an important biopolymer in lignocellulosic biomass, is key to sustainable material applications and advances in biorefinery. Over the past decade, deep eutectic solvents (DES) have appeared as environmentally friendly solvents for lignin extraction, with choline chloride-based DES being widely used. Choline chloride, though biodegradable, is synthesized using hydrochloric acid, making it not fully organic. In this study, a 100 % organic, natural deep eutectic fruit-based solvent (NADES) composed of citric acid and fructose was used for the first time for lignin extraction. An acid-free lignin recovery protocol was also developed, eliminating the need for the traditional acid precipitation method and bringing the entire process in line with green chemistry principles. NADES were produced at different molar ratios and pH values to optimize the lignin dissolution. At pH 1.4, a maximum yield of 9.50 % by weight and a recovery rate of 44.10 % were achieved. Scanning electron microscopy and elemental analysis confirmed the removal of non-lignin components, whereas ultraviolet spectroscopy, Fourier transform infrared spectroscopy, and X-ray diffraction confirmed the enrichment of lignin. The aromatic structure of lignin was preserved, ensuring high purity and no degradation of the aromatic structure. Thermogravimetric and differential scanning calorimetry analyses showed the thermal stability of the extracted lignin, while the activation energy (E) and elemental analysis indicated carbon enrichment. In this study, a novel lignin extraction method using 100 % organic fruit-based NADES combined with an acid-free recovery process is presented, which represents a significant advancement in this field.
木质素是木质纤维素生物质中的一种重要生物聚合物，对于可持续材料应用和生物精炼的进展至关重要。在过去十年中，深共熔溶剂（DES）已成为用于提取木质素的环境友好型溶剂，基于氯化胆碱的DES被广泛使用。氯化胆碱虽然可生物降解，但却是用盐酸合成的，这使其并非完全有机。在本研究中，首次使用由柠檬酸和果糖组成的100%有机、基于天然深共熔溶剂的水果基溶剂（NADES）来提取木质素。还开发了一种无酸木质素回收方案，无需传统的酸沉淀方法，并使整个过程符合绿色化学原则。制备了不同摩尔比和pH值的NADES以优化木质素的溶解。在pH值为1.4时，实现了9.50%的最大重量产率和44.10%的回收率。扫描电子显微镜和元素分析证实了非木质素成分的去除，而紫外光谱、傅里叶变换红外光谱和X射线衍射证实了木质素的富集。木质素的芳香结构得以保留，确保了高纯度且芳香结构未降解。热重分析和差示扫描量热分析显示了提取的木质素的热稳定性，而活化能（E）和元素分析表明了碳的富集。在本研究中，提出了一种使用100%有机水果基NADES结合无酸回收工艺的新型木质素提取方法，这代表了该领域的一项重大进展。
