Preparation of a Novel Zn(II)-Imidazole Framework as an Efficient and Regenerative Adsorbent for Pb, Hg, and As Ion Removal From Water
Zhen Huang, Minghu Zhao, Chen Wang, Shixing Wang, Linqing Dai, Libo Zhang
Abstract
and 3-amino-5-mercapto-1,2,4-triazole to eliminate toxic metal ions from water. Zn-MOF was detected via using Fourier-transform infrared (FTIR) spectroscopy, field-emission scanning electron microscopy (FESEM), Brunauer-Emmett-Teller (BET) analysis, and X-ray photoelectron spectroscopy (XPS). Zn-MOF is stable and has a very large surface area. The uptake properties of Zn-MOF were investigated. The maximum uptake capacity of Zn-MOF for Pb, Hg, and As ions was 1097, 32, and 718 mg/g, respectively. This was obtained at pH = 4, 5, and 6, respectively. The adsorption data is in good agreement with the Langmuir and pseudo-second-order rate models, indicating that the uptake process of Zn-MOF for toxic metal ions was a single layer uptake on a uniform surface via exchange of valence electrons. Thermodynamics shows that the uptake process is autogenic and endothermic. Zn-MOF can be reused at least 6 times. Mercury and lead strongly coordinated with Zn-MOF. The interaction between arsenic and Zn-MOF is weak chemical coordination and ion exchange. Zn-MOF has wide application prospects for toxic metal ion elimination.