South China Institute of Collaborative Innovation , South China University of Technology , Dongguan 221116 , Guangdong , P. R. China.
Biomacromolecules. 2019 Dec 9;20(12):4466-4475. doi: 10.1021/acs.biomac.9b01198. Epub 2019 Nov 22.
Simultaneous production and functionalization of cellulose nanofibrils (CNFs) for heavy metal ion removal is an economical and promising solution to expedite their use in water treatment. In this work, carboxymethylated CNFs (CMCNFs) with a carboxylate content up to 2.7 mmol/g are prepared by a combination of carboxymethylation and homogenization, which show diameters of 3.40-3.53 nm and lengths of 1210.6-383.3 nm. The effect of experimental conditions (including pH, carboxylate content, contact time, initial Cu concentration) on the removal performance of CMCNFs for Cu is investigated in detail. Adsorption performances of CMCNFs present a record high equilibrium Cu removal capacity of 115.3 mg/g at pH 5.0. Additionally, the underlying mechanism for the removal of Cu ions was uncovered by coupling the fitting results based on pseudo-second-order kinetic and Langmuir isotherm models with various characterizations such as scanning electron microscopy, energy dispersive spectroscopy (EDS), EDS mapping, X-ray photoelectron spectroscopy, atomic force microscopy, and powder X-ray diffraction. Finally, the potential application of CMCNF-2.7 with high carboxylate content in converting copper-contaminated water into drinking water was demonstrated. CMCNFs provide a new selection for the design of novel nanocellulose-based materials for water treatments.
同时生产和功能化纤维素纳米纤维（CNFs）以去除重金属离子是一种经济且有前途的解决方案，可以加速其在水处理中的应用。在这项工作中，通过羧甲基化和均化的组合制备了羧甲基化纤维素纳米纤维（CMCNFs），其羧酸盐含量高达 2.7mmol/g，直径为 3.40-3.53nm，长度为 1210.6-383.3nm。详细研究了实验条件（包括 pH 值、羧酸盐含量、接触时间、初始 Cu 浓度）对 CMCNFs 去除 Cu 的性能的影响。CMCNFs 的吸附性能在 pH 值为 5.0 时表现出创纪录的高平衡 Cu 去除容量，为 115.3mg/g。此外，通过将基于伪二级动力学和 Langmuir 等温线模型的拟合结果与各种特性（如扫描电子显微镜、能谱（EDS）、EDS 映射、X 射线光电子能谱、原子力显微镜和粉末 X 射线衍射）相结合，揭示了去除 Cu 离子的潜在机制。最后，展示了具有高羧酸盐含量的 CMCNF-2.7 在将受污染的含铜水转化为饮用水方面的潜在应用。CMCNFs 为设计用于水处理的新型纳米纤维素基材料提供了新的选择。
