Ti_(3)C_(2)T_(x)/Ti_(3)AlC_(2)复合相的制备及其对染料吸附行为研究

Preparation of Ti_(3)C_(2)T_(x)/Ti_(3)AlC_(2) and its Adsorption Properties for Dyes

采用原位HF部分蚀刻MAX(Ti_(3)AlC_(2))制备了层状MXene/MAX(Ti_(3)C_(2)T_(x)/Ti_(3)AlC_(2))复合相,通过单因素分析法对3种染料亚甲基蓝(MB)、孔雀石绿(MG)和吖啶黄素(AF)进行吸附性能研究。采用X-射线衍射仪(XRD)、场发射扫描电子显微镜(FE-SEM)、全自动比表面及孔隙度分析仪(BET)对样品物相、晶体结构、形貌和比表面积进行了表征,系统研究了吸附剂投加量、染料初始浓度和溶液pH对Ti_(3)C_(2)T_(x)/Ti_(3)AlC_(2)复合相吸附MB、MG、AF这3种染料的性能影响。结果表明:Ti_(3)C_(2)T_(x)/Ti_(3)AlC_(2)复合相对MB、MG、AF这3种染料的最大去除效率分别为99.56%、99.86%和79.32%,最大吸附量分别为59.35、95.74、12.12 mg/g,均优于商用活性炭。同时,发现Ti_(3)C_(2)T_(x)/Ti_(3)AlC_(2)复合相对MB和MG的吸附效果对pH没有依赖性,对AF的吸附在酸性条件下效果更优。3种染料吸附等温模型均符合Freundlich模型,吸附动力学符合准二级动力学模型,吸附过程主要归因于Ti_(3)C_(2)T_(x)/Ti_(3)AlC_(2)复合相表面官能团参与的化学吸附以及静电作用共同控制。

The layered MXene/MAX(Ti_(3)C_(2)T_(x)/Ti_(3)AlC_(2))composites were prepared by in situ HF partial etching of MAX(Ti_(3)AlC_(2)).The adsorption properties of methylene blue(MB),malachite green(MG)and acridine flavin(AF)were investigated by single-factor analysis method.The physical phase,crystal structure,morphology and specific surface area of the samples were characterized by XRD,FE-SEM and BET.The effects of adsorbent dosing,initial concentration of dyes and pH on the adsorption performance of Ti_(3)C_(2)T_(x)/Ti_(3)AlC_(2) composites were systematically investigated.The results showed that the maximum removal efficiencies of Ti_(3)C_(2)T_(x)/Ti_(3)AlC_(2) composites for MB,MG and AF dyes were 99.56%,99.86%and 79.32%,respectively.The maximum adsorption capacities were 59.35,95.74,and 12.12 mg/g,respectively,which were better than those of commercial activated carbon.Meanwhile,it was found that the adsorption effect of Ti_(3)C_(2)T_(x)/Ti_(3)AlC_(2) composites on MB and MG was not dependent on pH,and the adsorption ability on AF was better under acidic conditions.The isothermal model for the adsorption of the three dyes were in accordance with the Freundlich model,and the adsorption kinetics were in accordance with the quasi-secondary kinetic model,which proved that the adsorption processes were mainly attributed to the joint control of chemisorption involving functional groups on the surface of Ti_(3)C_(2)T_(x)/Ti_(3)AlC_(2) composite phase as well as electrostatic interactions.