Amino-enriched Zn-MOFs with self-reduction for energy-free simultaneous removal and electrochemical detection of heavy metal ions in the aquatic environment

Abstract

Background

Heavy metal pollution is a global environmental problem. Self-reduction strategy has garnered attention in adsorption and electrochemical detection of heavy metal ions due to their operational simplicity and elimination of the need for external electrodeposition steps. Therefore, it is crucial to integrate self-reduction-based adsorption with electrochemical detection. Metal-Organic Frameworks (MOFs) have demonstrated successful applications in adsorption and electrochemical detection. Moreover, owing to the presence of organic ligands featuring amino and electron-rich aromatic ring moieties, MOFs possess reducing capabilities towards metal ions.

Results

Herein, 2,4,6-triaminopyrimidine, characterized by its abundance of amino and electron-rich aromatic ring constituents, was selected as the organic ligand for the synthesis of Zn-MOFs, showcasing their efficacy in self-reduction-based adsorption and electrochemical detection of heavy metal ions. The Zn-MOFs exhibited swift uptake of heavy metal ions, boasting a remarkable adsorption capacity (4624 mg/g for Cu(II), 4261 mg/g for Hg(II), and 4874 mg/g for Pb(II)), while also exhibiting low detection limits (0.17 μg/L for Cu(II), 0.25 μg/L for Hg(II), and 0.22 μg/L for Pb(II)) in the electrochemical detection of heavy metal ions.

Significance

In this work, amino-rich Zn-MOFs were prepared for self-reducing adsorption and electrochemical detection of heavy metal ions, providing promising material for the detection and removal of heavy metal ions, offering a new method for the effective elimination and rapid detection of heavy metal ions, and pointing out a promising path for the treatment and monitoring of environmental issues.