An enhanced adsorption of organic dyes onto NH2 functionalization titanium-based metal-organic frameworks and the mechanism investigation
An enhanced adsorption of organic dyes onto NH2 functionalization titanium-based metal-organic frameworks and the mechanism investigation
复制标题
NH2功能化钛基金属有机骨架对有机染料的增强吸附及其机理研究
DOI：
10.1016/j.micromeso.2017.12.016
复制
发表时间：
2018-06-01
影响因子：
5.2
通讯作者：
Qi, Shi-Hua
中科院分区：
文献类型：
--
作者：
Fan, Yu-Han;Zhang, Shou-Wen;Qi, Shi-Hua
本文研究了NH 2功能化钛基金属有机骨架（NH 2-MIL-125（Ti））对多种有机染料的增强吸附性能及机理。首先，成功地合成并表征了MIL-125（Ti）和NH 2-MIL-125（Ti）。通过刘易斯酸碱相互作用，Fe 3 O 4纳米粒子吸附在Ti-MOFs表面，可使Ti-MOFs磁化。通过对三种染料（阳离子染料、阴离子染料和还原染料）的吸附测试，发现静电相互作用、π-π堆积相互作用和孔填充作用在两种Ti-MOFs的吸附过程中均起重要作用。特别地，NH 2-MIL-125（Ti）中的氨基可以提供针对目标物质的额外氢键相互作用，这导致比MIL-125（Ti）更强的相互作用力和更高的吸附容量。吸附动力学和吸附等温线表明，两种Ti-MOFs对亚甲基蓝（MB）的吸附过程均符合准二级动力学和Freundlich吸附等温式。吸附热力学实验表明，MB在两种Ti-MOFs上的吸附都是自发的。但它们的焓值和熵值却相反，表明它们的吸附过程分别受焓效应和熵效应控制。
In this paper, the enhanced adsorption properties and mechanism of NH2 functionalization titanium-based metal-organic frameworks (NH2-MIL-125(Ti)) towards various organic dyes was investigated. First, MIL-125(Ti) and NH2-MIL-125(Ti) were successfully synthesized and characterized. The as-prepared Ti-MOFs can be facilely magnetized by adsorbing Fe3O4 nanoparticles on their surfaces via a Lewis acid-base interaction. Then, three types of dye (cationic dye, anionic dye and vat dye) adsorption measurements show that the electrostatic interaction, pi-pi stacking interaction and pore filling all play important roles in the adsorption process of both Ti-MOFs in aqueous solutions. Particularly, the amino group in NH2-MIL-125(Ti) can provide extra hydrogen bonding interaction towards target substances, which results in a stronger interaction force and a higher adsorption capacity than that of MIL-125(Ti). The adsorption kinetics and isotherm suggested the adsorption process of both Ti-MOFs towards methylene blue (MB) were better fitted to a pseudo-second-order kinetic and Freundlich isotherm model. The adsorption thermodynamic experiments demonstrated that adsorption of MB on both Ti-MOFs was spontaneous. However, their values of enthalpy and entropy were opposite, indicating that their adsorption processes were controlled by enthalpy and entropy effect, respectively.