磺酸基改性二维Ti3C2Tx纳米材料制备与Pb2+吸附性能

对二维Ti₃C₂T_x材料进行了磺酸基团接枝改性(Ti₃C₂T_x—SO₃H)，表征了改性前后微观结构的变化，研究了对重金属Pb2+的吸附行为与机制。XRD、FTIR及EDS表明磺酸基团在Ti₃C₂T_x表面成功接枝，而SEM则发现Ti₃C₂T_x?SO₃H呈现较Ti₃C₂T_x更轻薄的层状结构。改性后，Ti₃C₂T_x—SO₃H对重金属Pb2+20 min内达到吸附平衡，最大吸附量达到733.6 mg·g?1，较Ti₃C₂T_x吸附量提升了23%，且吸附量随着pH(2~6)的增加而逐渐增大，在Mg2+、Ca2+、Co2+、Zn2+等共存离子的干扰下，仍保持较高的吸附水平。机制分析表明，改性前后吸附过程均符合准二级动力学模型和Langmuir吸附等温线拟合模型，以单分子层化学吸附为主，但由于磺酸基团提供了更多的吸附饱和活性位点，并提高了Ti₃C₂T_x在水溶液中的分散性，使改性后对Pb2+吸附性能更优异。 

Study on preparation of two-dimensional Ti3C2Tx nanomaterials modified by sulfonic acid groups and the adsorption performance of lead(II) ion

The two-dimensional Ti₃C₂T_x was modified by sulfonic acid group grafting (abbreviated as Ti₃C₂T_x—SO₃H), and its microstructure before and after the modification was characterized. The adsorption behavior and mechanism of heavy metal Pb2+ by the Ti₃C₂T_x—SO₃H were also investigated. XRD, FTIR and EDS analyses indicate that sulfonic acid group is successfully grafted on the surface of the Ti₃C₂T_x, while SEM shows that the Ti₃C₂T_x—SO₃H has a lighter and thinner layered structure than the Ti₃C₂T_x. Pb2+ adsorption by the Ti₃C₂T_x—SO₃H reaches equilibrium within 20 minutes. The maximum adsorption capacity of the Ti₃C₂T_x—SO₃H is 733.6 mg·g?1, which is 23% higher than the Ti₃C₂T_x. And Pb2+ adsorption capacity by the Ti₃C₂T_x—SO₃H gradually increases with the increase of pH (2-6). Under the interference of coexisting ions such as Mg2+, Ca2+, Co2+ and Zn2+, the Ti₃C₂T_x-SO₃H still maintains a high level of Pb2+ adsorption. Pb2+ adsorption processes by both the Ti₃C₂T_x and the Ti₃C₂T_x—SO₃H fit well the pseudo second kinetic model and Langmuir isotherm model, suggesting that the adsorption processes are monolayer chemisorption. The Ti₃C₂T_x—SO₃H shows more excellent adsorption performance towards Pb2+ after adsorption mainly due to the more active sites provided by sulfonic acid group and the enhanced dispersion in aqueous solution.