改性木质素基生物炭的制备及其对全氟类化合物吸附性能研究

Preparation of Modified Lignin-Based Biochar and Its Adsorption Performance for Perfluoroalkyl Substances

摘要: 本研究以酶解木质素为原料，经水热预处理(尿素为氮源)与KOH活化的复合工艺，成功制备出分级多孔碳吸附剂(K-NHPC)，用于探究对全氟类化合物(以OBS为代表)的吸附性能。结果表明：所制备的K-NHPC具有高比表面积、丰富孔隙结构及均匀分散的氮元素，吸附实验结果表明，K-NHPC对OBS的吸附性能优异，且该吸附过程符合伪二级动力学模型和Langmuir吸附等温线模型，说明吸附以化学吸附为主导、伴随物理吸附的单分子层吸附。热力学分析显示该过程为自发、吸热的熵增过程，ΔG均为负值。本研究为高效去除水中全氟化合物提供了一种新型吸附材料，具有一定的应用潜力。

Abstract: This study utilized enzymatic hydrolysis lignin as the raw material and successfully fabricated a hierarchical porous carbon adsorbent (K-NHPC) through a combined process involving hydrothermal pretreatment (with urea as the nitrogen source) and KOH activation, aiming to explore its adsorption performance toward perfluoroalkyl substances (represented by OBS). The results indicated that the prepared K-NHPC possessed a high specific surface area, abundant pore structure, and uniformly dispersed nitrogen elements. Adsorption experiments demonstrated that K-NHPC exhibited excellent adsorption performance for OBS, and the adsorption process conformed to the pseudo-second-order kinetic model and the Langmuir adsorption isotherm model, indicating monolayer adsorption dominated by chemical adsorption accompanied by physical adsorption. Thermodynamic analysis revealed that the process was spontaneous, endothermic, and entropy-increasing, with all ΔG values being negative. This study provides a novel adsorbent material for the efficient removal of perfluoroalkyl substances from water, demonstrating promising application potential.