The mode of action of heavy metal ions on the surface of Fe/Mg/Ni intercalated materials and the realization of selective detection of Pb(II)
Recently, the research team of the Institute of Intelligent Machinery, Institute of Hefei Institute of Physical Science, Chinese Academy of Sciences, Huang Xingjiu's research group combined XPS technology to study the mechanism of heavy metal ions and Fe/Mg/Ni intercalation nanomaterials (Fe/Mg/Ni-LDH). Successfully achieved highly selective detection of Pb(II). Related research results have been published in the Journal of Hazardous Materials.
Due to the existence of a large number of coexisting ions in the actual water environment, how to achieve a highly sensitive and interference-free detection of the target harmful heavy metal ions has been a great challenge in the field of electroanalysis. The previous research work of the research group found that the electrochemical detection performance of heavy metals on nanomaterials is closely related to the adsorption performance of heavy metal ions. However, there are still many deficiencies in how to obtain nanomaterials with selective adsorption of heavy metal ions and their selective mechanism.
The research group selected iron-based layered bis-hydroxy complex metal oxide intercalation materials with excellent adsorption properties to construct an electrochemically sensitive interface and be used for the detection of Pb(II) selectivity. The researchers conducted a careful and in-depth study of the selective detection of Pb(II) with Fe/Mg/Ni nanomaterials in combination with XPS technology. The results of the study show that different heavy metal ions have different ways of interacting with the metal hydroxyl bonds exposed on the surface of nanomaterials. The coexisting interfering ions of Cd(II), Zn(II), Cu(II), and Hg(II) mostly bind to dissociated hydroxyl groups (-O-) in a non-specifically binding electrostatic interaction, while Pb(II) More often, MO-Pb (M=Fe, Mg, Ni) is formed by the combination of specific binding and undissociated hydroxyl groups. In addition, the undissociated hydroxyl groups on the surface of Fe/Mg/Ni-LDH nanomaterials are significantly more than the dissociated hydroxyls under the optimal conditions for detection. This differential action on different heavy metal ions leads to selectivity. The adsorption, thus finally achieving selective detection. The researchers found that Fe/Mg/Ni intercalation nanomaterials can achieve highly selective and non-invasive detection of Pb(II) in aqueous environment, with high sensitivity (68.1 μA μM-1) and low detection limit. (0.032 μM). The work organically combines the adsorption properties and electrochemical behavior of nano-materials on heavy metal ions, and provides a novel method for the development of new nano-materials for the actual water electrochemical analysis.
The research work was supported by the National Natural Science Foundation of China and the Innovation Crossing Team of the Chinese Academy of Sciences.
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