Hou Yanwei, Lin Shanna, Fan Jiajun, Zhang Youchi, Jing Guohua, Cai Chao
College of Chemical Engineering, Huaqiao University, Xiamen 361021, China.
Key Lab of Urban Environment and Health, Institute of Urban Environment, Chinese Academy of Sciences, Xiamen 361021, China.
Toxics. 2024 Sep 30;12(10):717. doi: 10.3390/toxics12100717.
In the environmental field, the advancement of new high-efficiency heavy metal adsorption materials remains a continuous research focus. A novel composite, covalent organic framework-modified biochar (RH-COF), was fabricated via an in-situ polymerization approach in this study. The COF-modified biochar was characterized by elemental analysis, BET analysis, SEM, FT-IR, and XPS. The nitrogen and oxygen content in the modified material increased significantly from 0.96% and 15.50% to 5.40% and 24.08%, respectively, indicating the addition of a substantial number of nitrogen- and oxygen-containing functional groups to the RH-COF surface, thereby enhancing its adsorption capacity for Cd from 4.20 mg g to 58.62 mg g, representing an approximately fourteen-fold increase. Both the pseudo-second-order model and the Langmuir model were suitable for describing the kinetics and isotherms of Cd adsorption onto RH-COF. The adsorption performance of Cd by RH-COF showed minimal sensitivity to pH values between 4.0 and 8.0, but could be slightly influenced by ionic strength. Mechanistic analysis showed that the Cd adsorption on RH-COF was dominated by surface complexation and chelation, alongside electrostatic adsorption, surface precipitation, and Cπ-cation interactions. Overall, these findings suggest that the synthesis of COF-biochar composite may serve as a promising remediation strategy while providing scientific support for applying COF in environmental materials.
在环境领域，新型高效重金属吸附材料的研发一直是持续的研究重点。本研究通过原位聚合法制备了一种新型复合材料——共价有机框架修饰生物炭（RH-COF）。采用元素分析、BET分析、扫描电子显微镜（SEM）、傅里叶变换红外光谱（FT-IR）和X射线光电子能谱（XPS）对COF修饰生物炭进行了表征。改性材料中的氮和氧含量分别从0.96%和15.50%显著增加到5.40%和24.08%，这表明在RH-COF表面添加了大量含氮和含氧官能团，从而使其对镉的吸附容量从4.20 mg/g提高到58.62 mg/g，增长了约14倍。准二级模型和朗缪尔模型均适用于描述镉在RH-COF上的吸附动力学和等温线。RH-COF对镉的吸附性能在pH值4.0至8.0之间对pH值的敏感性最小，但会受到离子强度的轻微影响。机理分析表明，镉在RH-COF上的吸附主要由表面络合和螯合作用主导，同时伴有静电吸附、表面沉淀和Cπ-阳离子相互作用。总体而言，这些研究结果表明，COF-生物炭复合材料的合成可能是一种有前景的修复策略，同时为COF在环境材料中的应用提供了科学支持。
