Abstract
Bi2O3 was proven an attractive compound for electrode modification in heavy metal electrochemical analysis. A novel method for synthesizing Bi2O3-attached multiwalled carbon nanotubes (Bi2O3@CNTs) in solution is successfully developed in this study. Characteristics of the obtained Bi2O3@CNTs were proven by modern techniques such as X-ray diffraction, Raman spectroscopy, scanning electronic microscopy, transmission electron microscopy, cyclic voltammetry, electrochemical impedance spectroscopy, and anodic stripping voltammetry. Microscopy images and spectra results reveal that Bi2O3 particles are mainly attached at defect points on multiwalled carbon nanotubes (MWCNTs) walls. Paste electrodes based on the MWCNTs and synthesized Bi2O3@CNTs were applied for electrochemical measurements. The redox mechanism of Bi2O3 on the electrode surface was also made clear by the cyclic voltammetric tests. The recorded cyclic voltammograms and electrochemical impedance spectroscopy demonstrate that the Bi2O3@CNTs electrode was in lower charge transfer resistance than the CNTs one and in the controlled diffusion region. Investigation on the electrochemical behavior of Pb2+ at the Bi2O3@CNTs electrodes found a significant improvement of analytical response, resulting in 3.44 μg/L of the detection limit and 2.842 μA/(μg/L) of the sensitivity with linear sweep anodic stripping voltammetry technique at optimized conditions.
Highlights
Researchers are focusing on controlling the level of heavy metals in waterways through developing novel sensors for detecting heavy metals such as lead
This study is aimed at developing a new method for preparing Bi2O3-attached multiwalled carbon nanotubes (Bi2O3@Carbon nanotubes (CNTs)) for paste electrode construction
These two peaks indicate the existence of amorphous phases in the CNTs owing to their low intensity and large width
Summary
Researchers are focusing on controlling the level of heavy metals in waterways through developing novel sensors for detecting heavy metals such as lead. As low concentrations of lead (II) can cause severe ecological damage and harm human health (such as anemia, weakness, and kidney and brain damage) [1], developing a fast and highly efficient method for accurately detecting lead in wastewater is extremely necessary. Anodic stripping voltammetry (ASV) is a powerful, sensitive and selective electrochemical technique for determining heavy metal ions such as Pb [1]. These ionic species are first deposited on the working electrode (WE) in the accumulation step under a reduction potential. These redox processes occur on the WE surface, where mass and electrons are transported, and these processes depend significantly on the properties of the electrode material
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