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Highly sensitive and highly selective detection of Pb(II) in China has progressed
[ China Instrumentation Network Instrument Development ] Recently, the intelligent institute postdoctoral Yang Meng used MoS2/RGO nanocomposites to achieve high sensitivity and high selectivity detection of micro-pollutants Pb(II) in water. This work has important scientific significance for the selectivity and accurate detection of heavy metal ions in actual water samples. The relevant results have been published in the journal Analytica Chimica Acta of Elsevier (2019, DOI: 10.1016/j.aca.2019.03.008).
When the heavy metal ions are detected by stripping voltammetry, there are many reasons such as the formation of intermetallic compounds between different heavy metal ions during the enrichment process, which causes serious interference when simultaneously detecting a plurality of heavy metal ions, and cannot accurately detect a specific one. heavy metal ion. Therefore, exploring the sensitive and selective detection of the physical properties of nanomaterials and heavy metal ions has been a challenging and meaningful work in electroanalytical chemistry.
MoS2 is widely studied as a typical two-dimensional transition metal chalcogenide material, but it is rarely used in electrochemical detection due to its lack of active sites for reaction with heavy metals. This work improves the electrochemical sensing activity of MoS2 nanosheets by combining MoS2 with reduced conductivity graphite (RGO) with good electrical conductivity. The researchers explored the anodic stripping voltammetric behavior of heavy metal ions in the electrochemically sensitive interface constructed by MoS2/RGO nanocomposites.
The results show that the proposed analytical method can achieve high sensitivity, high selectivity and high anti-interference detection for Pb(II). Adsorption experiments show that the adsorption capacity of different heavy metal ions on the surface of MoS2/RGO nanocomposites is very different. The adsorption of Pb(II) by MoS2/RGO nanocomposites is much larger than that of other ions. Researchers further studied the interaction between MoS2/RGO nanocomposites and Pb(II) by X-ray photoelectron spectroscopy. Studies have shown that Pb(II) and -SOH in MoS2/RGO nanocomposites are more likely to form Pb. -O bond, therefore, the MoS2/RGO nanocomposite has a large adsorption capacity for Pb(II).
Adsorption of more Pb(II) during the enrichment phase of the stripping voltammetry reduces the deposition of more Pb(0) onto the electrode surface. Due to the good conductivity of the modified electrode, it can significantly promote in situ reduction-reoxidation. The reaction occurs, which greatly enhances the electrochemical elution signal. Therefore, the electrochemically sensitive interface constructed by MoS2/RGO nanocomposites can achieve high sensitivity and high selectivity detection of Pb(II).
The proposed method is used to detect Pb(II) in the water sample of the sewage treatment plant, and obtain accurate test results and satisfactory recovery rate, indicating that the analytical method has the detection of Pb(II) in the actual water sample. Application potential.
The research work was supported by the National Natural Science Foundation of China, the Postdoctoral Innovative Talent Support Program, the 13th Five-Year Plan Support Project of the Hefei Institute of Material Science, Chinese Academy of Sciences, and the Natural Science Foundation of Anhui Province.
(Original title: Intelligent Institute of High-sensitivity, high-selectivity and accurate detection of heavy metal pollutants Pb(II))