Preparation of a Novel Zn(II)-Imidazole Framework as an Efficient and Regenerative Adsorbent for Pb, Hg, and As Ion Removal From Water

Abstract

An outstanding metal–organic framework sorbent (Zn-MOF) was prepared using Zn2+ 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.

CuII Ion Doping Enhances the Water Stability of Luminescent Metal–Organic Framework, Realizing the Detection of Fe3+ and Antibiotics in Aqueous Solutions

“…The vibration band at 1,589 cm −1 and 1,389 cm −1 of the five complexes can be associated with the asymmetrical stretching vibration and symmetrical stretching vibration of -COO-, respectively. The observed band at 1,653 cm −1 in the FTIR spectrum of Zn-MOF is assigned as the stretching vibration of the -C=N- bond ( Huang et al, 2020 ), which migrates to the lower band with Cu ion doping (Cu 0.01 /Zn-MOF: 1,653 cm −1 , Cu 0.1 /Zn-MOF: 1,651 cm −1 , Cu 0.2 /Zn-MOF: 1,647 cm −1 , Cu 0.5 /Zn-MOF: 1,639 cm −1 ), probably due to competitive coordination between Cu 2+ and Zn 2+ . The signals at 455 cm −1 can be attributed to the stretching vibration of Zn–O.…”

Chemistry and Nanotechnology‐Oriented Strategies toward Nanocellulose for Human Water Treatment

“…The main mechanism for the illumination of heavy metal removal over nanocellulose is derived from ion exchange and chemical complexation. [90][91][92][93][94][95][96] With regards to the ion exchange mechanism, the surface active sites of the adsorbents were occupied by the adsorbed heavy metal ions. With regards to both the ion exchange and chemical complexation mechanisms, the maximum adsorption capacity of heavy metal ions is controlled by stoichiometry rules, which cannot exceed half the content of ionic sites on the surface of adsorbent.…”

Metal Organic Frameworks to Remove Arsenic Adsorption from Wastewater

“…Huang Z et al carried out arsenic elimination from water using regenerative adsorbent Zn(II) imidazole framework (Zn-MOF) via solvothermal technique and exhibited high performance and potential application in wastewater treatment, which is shown in Fig. 9 [36]. Batch-wise experiments were carried for the elimination of heavy metals at different pH (1)(2)(3)(4)(5)(6).…”

“…Zinc metal and an organic linker are heated at 110 °C for 18 h to form the framework. Reprinted with the permission of ACS from [36] MOF is synthesized by a post-synthetic method [2]. The results show that more than 90% As(V) oxyanion from a 5 ppm solution was removed after 30 min with the ratio of As(V): Zr 6 as 0.29:1 and overall removal was evaluated after 3 h. For a demonstration of As(III) uptake, neutral As(III) was captured using thiolated ligand sites where acetic acid and hydrochloric acid were the modulators.…”