Pecheu Chancellin Nkepdep, Jiokeng Sherman Lesly Zambou, Tamo Arnaud Kamdem, Doungmo Giscard, Doench Ingo, Osorio-Madrazo Anayancy, Tonle Ignas Kenfack, Ngameni Emmanuel
Electrochemistry and Chemistry of Materials, Department of Chemistry, University of Dschang, Dschang P.O. Box 67, Cameroon.
Institut für Anorganische Chemie und Strukturchemie, Heinrich-Heine-Universität Düsseldorf, 40204 Düsseldorf, Germany.
Nanomaterials (Basel). 2022 Aug 25;12(17):2928. doi: 10.3390/nano12172928.
A talc-like magnesium phyllosilicate functionalized with amine groups (TalcNH), useful as sensor material in voltammetry stripping analysis, was synthesized by a sol-gel-based processing method. The characterizations of the resulting synthetic organoclay by scanning electron microscopy (SEM), X-ray diffraction, N sorption isotherms (BET method), Fourier transform infrared spectroscopy (FTIR), CHN elemental analysis and UV-Vis diffuse reflectance spectroscopy (UV-Vis-DRS) demonstrated the effectiveness of the process used for grafting of amine functionality in the interlamellar clay. The results indicate the presence of organic moieties covalently bonded to the inorganic lattice of talc-like magnesium phyllosilicate silicon sheet, with interlayer distances of 1568.4 pm. In an effort to use a talc-like material as an electrode material without the addition of a dispersing agent and/or molecular glue, the TalcNH material was successfully dispersed in distilled water in contrast to natural talc. Then, it was used to modify a glassy carbon electrode (GCE) by drop coating. The characterization of the resulting modified electrode by cyclic voltammetry (CV) and electrochemical impedance spectroscopy (EIS) revealed its charge selectivity ability. In addition, EIS results showed low charge transfer resistance (0.32 Ω) during the electro-oxidation of [Fe(CN)]. Kinetics studies were also performed by EIS, which revealed that the standard heterogeneous electron transfer rate constant was (0.019 ± 0.001) cm.s, indicating a fast direct electron transfer rate of [Fe(CN)] to the electrode. Using anodic adsorptive stripping differential pulse voltammetry (DPV), fast and highly sensitive determination of Pb(II) ions was achieved. The peak current of Pb ions on TalcNH/GCE was about three-fold more important than that obtained on bare GCE. The calculated detection and quantification limits were respectively 7.45 × 10 M (S/N = 3) and 24.84 × 10 M (S/N 10), for the determination of Pb under optimized conditions. The method was successfully used to tap water with satisfactory results. The results highlight the efficient chelation of Pb ions by the grafted NH groups and the potential of talc-like amino-functionalized magnesium phyllosilicate for application in electrochemical sensors.
通过基于溶胶 - 凝胶的加工方法合成了一种用胺基官能化的滑石状镁层状硅酸盐（TalcNH），它可用作伏安溶出分析中的传感器材料。通过扫描电子显微镜（SEM）、X射线衍射、N吸附等温线（BET法）、傅里叶变换红外光谱（FTIR）、CHN元素分析和紫外 - 可见漫反射光谱（UV - Vis - DRS）对所得合成有机粘土进行表征，证明了用于在层间粘土中接枝胺官能团的过程的有效性。结果表明存在与滑石状镁层状硅酸盐硅片的无机晶格共价键合的有机部分，层间距离为1568.4皮米。为了在不添加分散剂和/或分子胶水的情况下将滑石状材料用作电极材料，与天然滑石不同，TalcNH材料成功地分散在蒸馏水中。然后，通过滴涂将其用于修饰玻碳电极（GCE）。通过循环伏安法（CV）和电化学阻抗谱（EIS）对所得修饰电极进行表征，揭示了其电荷选择性能力。此外，EIS结果表明在[Fe(CN)]的电氧化过程中电荷转移电阻较低（0.32Ω）。还通过EIS进行了动力学研究，结果表明标准异相电子转移速率常数为(0.019 ± 0.001) cm·s，表明[Fe(CN)]向电极的直接电子转移速率很快。使用阳极吸附溶出差分脉冲伏安法（DPV），实现了对Pb(II)离子的快速、高灵敏度测定。TalcNH/GCE上Pb离子的峰值电流比裸GCE上获得的峰值电流大约高三倍。在优化条件下测定Pb时，计算得到的检测限和定量限分别为7.45×10⁻⁸ M（S/N = 3）和24.84×10⁻⁸ M（S/N = 10）。该方法成功用于自来水检测，结果令人满意。结果突出了接枝的NH基团对Pb离子的有效螯合作用以及滑石状氨基官能化镁层状硅酸盐在电化学传感器中的应用潜力。
