Fe3O4 and MnO2 assembled on halloysite nanotubes: A highly efficient solid-phase extractant for electrochemical detection of mercury(II) ions
2016; Elsevier BV; Volume: 228; Linguagem: Inglês
10.1016/j.snb.2015.12.107
ISSN1873-3077
AutoresMaryam Fayazi, Mohammad Ali Taher, Daryoush Afzali, Ali Mostafavi,
Tópico(s)Analytical chemistry methods development
ResumoIn this study, a novel and simple magnetic electrochemical sensing protocol for the sensitive detection of Hg(II) in aqueous media was demonstrated. For this purpose, the halloysite nanotubes-iron oxide–manganese oxide nanocomposite (HNTs-Fe3O4–MnO2) was successfully synthesized for the first time. The synthesis process involves the deposition of Fe3O4 nanoparticles on the surface of HNTs using a simple chemical precipitation method, subsequent formation of wire-like MnO2 nanoparticles on the surface of HNTs-Fe3O4 composites by hydrothermal method with potassium permanganate (KMnO4) and ammonium persulfate ((NH4)2S2O8). The resulting HNTs-Fe3O4–MnO2 nanocomposite was suspended in mercury solution and then brought on the surface of a magnetic carbon paste electrode (MCPE). The amount of analyte was detected electrochemically by applying differential pulse voltammetry (DPV). The conditions of extraction and voltammetric determination were studied and optimized. The proposed method exhibited a linear relationship towards Hg(II) concentrations ranging from 0.5 to 150 μg L−1. The detection limit achieved was 0.2 μg L−1 (3Sb/m), which is lower than the US Environmental Protection Agency (EPA) standard (2 μg L−1 for drinkable water). The proposed methodology was applied for quantification of Hg(II) in real water samples and good recoveries were obtained from 96.0 to 102.7%.
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