MIL-101(Fe)对不同络合态Cr(Ⅲ)的吸附机制  

Adsorption mechanism of MIL-101(Fe)for different complexed Cr(III)

作　　者：屈婷婷 马宏瑞 张静 郝永永 王家宏 QU Tingting;MA Hongrui;ZHANG Jing;HAO Yongyong;WANG Jiahong(College of Environmental Science and Engineering,Shaanxi University of Science&Technology,Xi'an 710021,China;College of Bioresources Chemical and Materials Engineering,Shaanxi University of Science&Technology,Xi'an 710021,China)

机构地区：[1]陕西科技大学环境科学与工程学院,西安710021 [2]陕西科技大学轻工科学与工程学院,西安710021

出　　处：《化学工业与工程》2024年第6期91-100,共10页Chemical Industry and Engineering

基　　金：国家自然科学基金项目(22076113);陕西省博士后基金(2023BSHEDZZ277)

摘　　要：铁基MOF材料因其具有较多不饱和过渡金属位点,对重金属具有良好的结合机制。单宁(TA)因其水解产物相对分子质量的不确定性,使其与Cr(Ⅲ)形成的络合态重金属的吸附行为与小分子配合物如EDTA-Cr(Ⅲ)存在诸多差异。实验以TA-Cr(Ⅲ)为研究对象,选取MIL-101(Fe)为吸附材料,考察其对水中TA-Cr(Ⅲ)的吸附特征,并与其吸附EDTA-Cr(Ⅲ)的行为进行比较。结果表明,MIL-101(Fe)对于2种有机络合态Cr(Ⅲ)的吸附过程均符合伪二级动力学和Langmuir等温吸附模型,同等条件下TA-Cr(Ⅲ)的吸附量为277.79 mg·g^(-1),远大于其对EDTA-Cr(Ⅲ)的吸附量120.48 mg·g^(-1)。MIL-101(Fe)对TA-Cr(Ⅲ)吸附主要是Fe(Ⅲ)与—COOH及其水解产物没食子酸-Cr(Ⅲ)中的—OH分别发生配位和螯合作用,而对EDTA-Cr(Ⅲ)吸附主要是—COOH与Fe(Ⅲ)配位作用。在pH值为2~10范围内,材料表面的正电荷均与2种络合态Cr(Ⅲ)之间存在静电作用。Iron-based MOF materials have a good binding mechanism for complexed heavy metals due to their high number of unsaturated transition metal sites.Tannin(TA)has many differences in the adsorption behavior of heavy metals in the complexed formed with Cr(III)from small molecule complexes such as EDTA-Cr(III)due to the uncertainty in the molecular weight of its hydrolysis products.MIL-101(Fe)was selected as the adsorbent material and the TA-Cr(III)system was used as the mixed ligand complex to investigate the adsorption characteristics of TA-Cr(III)in water and to compare with the behavior of adsorbed EDTA-Cr(III).The results showed that the adsorption of MIL-101(Fe)for both organo-complexed Cr(III)belonged to the monolayer adsorption model.The adsorption amount of TA-Cr(III)was 277.79 mg·g^(-1)under the same conditions,which was much larger than its adsorption amount of 120.48mg·g^(-1)for EDTA-Cr(III).The adsorption of MIL-101(Fe)on TA-Cr(III)was mainly due to the chelation of Fe(III)with—OH in tannic acid and its hydrolysis product gallic acid,whereas the adsorption on EDTA-Cr(III)was mainly due to the liganding effect of—COOH with Fe(III)and to a lesser extent to electrostatic interactions between the positive charges on the surface of the material and the(EDTACr)^(-).

关 键 词：MIL-101(Fe) 吸附 络合态Cr(Ⅲ) 单宁酸 

分 类 号：X52[环境科学与工程—环境工程]