张杰阳,安晓强,崔雨琦,兰华春,李艳红.高分散氮化碳溶胶在重金属离子吸附去除中的应用[J].环境科学学报,2021,41(11):4509-4518
高分散氮化碳溶胶在重金属离子吸附去除中的应用
- Application of highly dispersed carbon nitride sol solution for the adsorption removal of heavy metal ions
- 基金项目：国家自然科学基金面上项目（No.51978373）
- 张杰阳
- 1. 桂林理工大学环境科学与工程学院, 桂林 541004;2. 清华大学水质与水生态研究中心, 北京 100084
- 安晓强
- 清华大学水质与水生态研究中心, 北京 100084
- 崔雨琦
- 清华大学水质与水生态研究中心, 北京 100084
- 兰华春
- 清华大学水质与水生态研究中心, 北京 100084
- 李艳红
- 桂林理工大学环境科学与工程学院, 桂林 541004
- 摘要：吸附材料在水中的分散性对于增加其与吸附质间相互作用，实现污染物的高效去除尤为重要.本文基于分子形态易于调控的石墨相氮化碳二维材料，通过简单的化学处理方法制备成高度分散于水中的溶胶吸附剂（M-C3N4-sol、U-C3N4-sol），通过透射电镜（TEM）、X射线衍射（XRD）、傅里叶变换红外光谱（FTIR）、X射线光电子能谱仪（XPS）、Zeta电位仪（Zeta Potential Analyzer）、比表面积及孔径分布仪（BET）等对其形貌、组成、结构进行了表征.结果表明，氮化碳溶胶呈现纳米级纤维状结构，在水中有着极佳的分散性.相较于原始氮化碳（g-C3N4），溶胶吸附剂对多种重金属离子的吸附去除能力得到大幅度提升，尤其是对Pb2+具有较高的吸附选择性.在298 K时，对Pb2+的吸附在1 min内即可达到平衡，快速吸附过程符合准二级动力学模型和Freundlich等温模型.吸附机理的研究表明，M-C3N4-sol对Pb2+的吸附是在静电引力、离子交换、氨基的表面络合和阳离子-π键的协同作用下完成的.吸附金属离子后，M-C3N4-sol发生脱稳形成易于实现固液分离的沉淀产物，对其进行稀硝酸脱附再生，吸附容量没有明显降低，表明其良好的循环使用性能.
- Abstract：The dispersion of adsorbents in water is particularly important for the efficient removal of pollutants by increasing the interactions between adsorbents and adsorbates. Herein, a simple chemical treatment method was used to prepare sol adsorbents (M-C3N4-sol, U-C3N4-sol) with high dispersivity in water. The morphology, composition and structure of the absorbents was characterized by TEM, XRD, FT-IR, XPS, Zeta Potential Analyzer and BET. The results showed that the dispersed carbon nitride exhibited a fibrous structure with nanoscale sizes. Compared to the pristine bulk carbon nitride, the adsorption capacity of sol adsorbents for various heavy metal ions was significantly improved, especially for Pb2+ in water. At 298 K, the adsorption equilibrium of Pb2+ was achieved within 1min. The rapid adsorption process accorded with the quasi-second-order kinetic model and the Freundlich isothermal model. Mechanism study revealed that the adsorption of Pb2+ by M-C3N4-sol was ascribed to the synergistic effect of electrostatic attraction, ion exchange, surface complexation of amino groups and cationic-π bond. After the adsorption of metal ions, M-C3N4-sol was destabilized to form precipitate products, which could be easily separated from water. The recycled adsorbents could be regenerated by dilute nitric acid, with ignorable decrease of adsorption capacity, suggesting its good recycling performance.
