纤维素纳米纤维(CNF)及其衍生物在重金属废水处理中的研究进展

Research Progress on Cellulose Nanofiber (CNF) and Its Derivatives in Heavy Metal Wastewater Treatment

摘要: 重金属水污染具有毒性强、生物累积性、难自然降解等特征，是水体污染治理的重点难题。传统重金属废水处理技术存在成本高、二次污染明显、固废产量大等短板。纤维素纳米纤维(Cellulose Nanofibril, CNF)来源于农林生物质资源，具备比表面积大、表面羟基丰富、可生物降解、易于表面功能化等突出优势，是一类极具发展潜力的绿色生物基吸附材料。但原始CNF仅依靠羟基实现重金属吸附，吸附容量有限、湿态结构稳定性差，限制实际工程应用。本文综述CNF及其衍生物的结构特性、主要改性策略，归纳羧基化、氨基接枝、无机杂化、交联复合等改性手段；阐述CNF基材料去除重金属离子的吸附机理，分析pH、离子强度、温度、竞争离子对吸附行为的影响；总结2D膜材料、3D气凝胶/水凝胶材料在重金属废水领域应用现状；讨论当前材料存在湿态力学不足、选择性差、规模化制备困难等瓶颈，展望CNF基吸附材料未来发展方向，为生物质基水处理吸附剂开发提供理论参考。

Abstract: Heavy metal water pollution is characterized by high toxicity, bioaccumulation, and difficulty in natural degradation, making it a key challenge in water pollution control. Traditional heavy metal wastewater treatment technologies suffer from drawbacks such as high cost, significant secondary pollution, and large solid waste generation. Cellulose nanofiber (CNF), derived from agricultural and forestry biomass resources, possesses outstanding advantages such as large specific surface area, abundant surface hydroxyl groups, biodegradability, and ease of surface functionalization, making them a promising class of green bio-based adsorbent materials. However, primitive CNF rely solely on hydroxyl groups for heavy metal adsorption, resulting in limited adsorption capacity and poor wet structural stability, which restricts practical engineering applications. This paper reviews the structural characteristics and main modification strategies of CNF and its derivatives, summarizing modification methods such as carboxylation, amino grafting, inorganic hybridization, and cross-linking and composite formation. It elucidates the adsorption mechanism of CNF-based materials for removing heavy metal ions, analyzing the effects of pH, ionic strength, temperature, and competing ions on adsorption behavior. The paper summarizes the current application status of 2D membrane materials and 3D aerogel/hydrogel materials in the field of heavy metal wastewater treatment. It discusses the current limitations of these materials, including insufficient wet mechanical properties, poor selectivity, and difficulties in large-scale preparation. Finally, it looks forward to the future development direction of CNF-based adsorbent materials, providing theoretical reference for the development of biomass-based water treatment adsorbents.