纤维素纳米纤维及其改性产物吸附重金属的研究进展

重金属污染是目前全世界面临的一个重大挑战，传统治理方法成本高、效率低等缺陷已不符合当今社会可持续发展战略。纤维素纳米纤维（cellulose nanofiber，CNF）因可再生、活性高、比表面积大和密度低等优点，在重金属吸附领域显示出巨大的应用潜力。本文主要综述了CNF的化学改性方法及其改性产物在水体系重金属离子吸附中的应用进展。首先对CNF的改性进行了系统的综述，主要包括化学接枝改性（羧基化、氨基化、巯基化、磷酸基化、磺酸基化和醛基化和硅烷化等）与接枝共聚改性。其次从结构设计方面重点阐述了改性CNF以气凝胶、水凝胶和复合膜等不同形态对水体系中重金属离子进行吸附的应用研究。最后，对CNF基重金属吸附剂的优缺点进行了讨论，指出了CNF基重金属吸附剂在局限性和适用性等方面的挑战，展望了CNF在水体系重金属离子去除领域的发展方向。

Research progress on adsorption of heavy metals by cellulose nanofibers and their modified products

Heavy metal pollution is still a major challenge around the world. Traditional treatment methods have unqualified to the sustainable development strategy due to high cost, environment pollution, low efficiency, etc. Cellulose nanofibers (CNF) have a bright application prospect due to rich sources, renewable, high activity, large specific surface area and low density, which has been widely applied in environment, food, agriculture fields for the adsorption of heavy metal in recent years. In this paper, the chemical modification methods of CNF and the application progress of the modified products in the adsorption of heavy metal ions in water system are reviewed. Firstly, the modification of CNF is summarized systematically, including chemical graft modification (carboxylation, amination, hydrophobicity, phosphorylation, sulfonic acid group, aldehyde group, silanization, etc.) and graft copolymerization modification. Secondly, from the aspect of structural design, the application of modified CNF in adsorption of heavy metal ions in water system by different forms such as aerogel, hydrogel and composite membrane is emphatically expounded. Finally, the advantages and disadvantages of CNF-based heavy metal adsorbents are discussed, the limitations and applicability of CNF-based heavy metal adsorbents are pointed out, and the development direction of CNF in the field of heavy metal ion removal in water system is prospected.