Zhang Haibo, Wen Jia, Fang Ying, Zhang Siyu, Zeng Guangming
College of Environmental Science and Engineering, Hunan University, Changsha 410082, PR China; Key Laboratory of Environmental Biology and Pollution Control (Hunan University), Ministry of Education, Changsha 410082, PR China.
College of Environmental Science and Engineering, Hunan University, Changsha 410082, PR China; Key Laboratory of Environmental Biology and Pollution Control (Hunan University), Ministry of Education, Changsha 410082, PR China.
J Colloid Interface Sci. 2019 Sep 1;551:155-163. doi: 10.1016/j.jcis.2019.05.016. Epub 2019 May 6.
Modification of MIL-100(Fe) with ethanediamine (ED) is expected to improve the removal percentage of Pb(II) ions from aqueous solution. Nevertheless, the adsorption performance of ED-MIL-100(Fe) in natural waters will be affected by natural organic matter such as fulvic acids (FA). Hence, it is necessary to study the influence of FA on the physicochemical property, adsorption behavior and mechanisms of ED-MIL-100(Fe) towards the removal of Pb(II) from water.
Batch adsorption experiments were conducted to compare adsorption capacity of MIL-100(Fe) and ED-MIL-100(Fe) for Pb(II). In addition, XRD, FTIR, SEM and XPS techniques were applied to investigate the characteristics, adsorption isotherms, and kinetics in the presence and absence of FA.
ED-MIL-100(Fe) enabled 99% removal of Pb(II) from water at or below 60 mg L, whereas the MIL-100(Fe) hardly adsorbed any Pb(II). Additionally, the adsorption percentage of the Pb(II) ions (76%) outcompeted that of other metal ions (i.e. Co, Cu, Ni, Zn, and Cd) (each ≤ 25%) in the mixed solution. The negative surface charge of ED-MIL-100(Fe) was not affected by FA. Increasing FA concentration steadily increased the functional groups surrounding the ED-MIL-100(Fe) via electrical interaction, thus facilitating the Pb(II) ions adsorption.
用乙二胺（ED）对MIL-100（Fe）进行改性有望提高从水溶液中去除Pb（II）离子的百分比。然而，ED-MIL-100（Fe）在天然水中的吸附性能会受到诸如富里酸（FA）等天然有机物的影响。因此，有必要研究FA对ED-MIL-100（Fe）去除水中Pb（II）的物理化学性质、吸附行为及机制的影响。
进行了批量吸附实验，以比较MIL-100（Fe）和ED-MIL-100（Fe）对Pb（II）的吸附容量。此外，应用X射线衍射（XRD）、傅里叶变换红外光谱（FTIR）、扫描电子显微镜（SEM）和X射线光电子能谱（XPS）技术研究了在有和没有FA存在的情况下的特性、吸附等温线和动力学。
在60mg/L及以下时，ED-MIL-100（Fe）能从水中去除99%的Pb（II），而MIL-100（Fe）几乎不吸附任何Pb（II）。此外，在混合溶液中，Pb（II）离子的吸附百分比（76%）高于其他金属离子（即Co、Cu、Ni、Zn和Cd）（每种均≤25%）。ED-MIL-100（Fe）的负表面电荷不受FA影响。随着FA浓度的增加，通过电相互作用稳定地增加了ED-MIL-100（Fe）周围的官能团，从而促进了Pb（II）离子的吸附。
