Exploring UiO-66(Zr) frameworks as nanotraps for highly efficient removal of EDTA-complexed heavy metals from water

• Published in: Journal of environmental chemical engineering Vol. 9; no. 1; p. 104932
• Main Authors: Lou, Xiaofei, Wu, Yi-nan, Kabtamu, Daniel Manaye, Matović, Ljiljana, Zhang, Yanxing, Sun, Xianyi, Schott, Eduardo, Chu, Wenhai, Li, Fengting
• Format: Journal Article
• Language: English
• Published: Elsevier Ltd 01-02-2021
• Subjects: Adsorption; DFT calculation; Metal-EDTA complexes; Metal–organic frameworks; UiO-66(Zr); UiO-66(Zr); Metal-EDTA complexes; DFT calculation; Adsorption; Metal–organic frameworks
• ISSN: 2213-3437; 2213-3437
• DOI: 10.1016/j.jece.2020.104932

Metal-organic frameworks (MOFs), an exciting class of porous crystalline materials, are suitable for adsorptive removal of toxic heavy metal-ethylenediaminetetraacetic acid (M-EDTA) complexes from wastewater. In this paper, water-stable UiO-66(Zr) with well-defined morphology was successfully synthesized through a facile microwave-assisted solvothermal method and employed as nanotraps for the efficient capture of the three M-EDTA complexes, Cu-EDTA, Pb-EDTA, and Ni-EDTA. The adsorption behaviors, effects of solution pH and co-existing anions, as well as the eluant and desorption were investigated. The obtained UiO-66(Zr) showed good stability and excellent uptake capacity of M-EDTA in a wide pH range (3.0–10.0). UiO-66(Zr) exhibited a higher removal efficiency of Cu-EDTA (57.56 mg/g), Pb-EDTA (120.6 mg/g), and Ni-EDTA (54.27 mg/g). Based on the overall analysis results, our findings show that EDTA-metal complex ions can be adsorbed inside UiO-66(Zr) mainly through the Lewis‐acid/‐base interactions and possible anion-π interaction with strong binding energies. Size-matching EDTA-metal complexes confined in the UiO-66(Zr) with flexible geometry would also contribute to the fast adsorption kinetics as well as the selective adsorption of different M-EDTA complexes.
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•Water-stable UiO-66(Zr) employed as “Nanotraps” for efficient capture of the heavy metals–EDTA complexes.•UiO-66(Zr) exhibited excellent and steady uptake performance in a wide pH range.•Adsorption mechanisms were investigated comprehensively through both experimental and theoretical methods.