BiW9-based electrochemical sensor for the simultaneous determination of cadmium(II) and lead(II) in water

Heavy metal pollution has been considered as an important concern for the environment, and effective detection methods are crucial for the sensitive and selective determination of toxic heavy metal ions such as lead and cadmium. Among various detection methods, electrochemical stripping analysis has been regarded as an efficient approach for the determination of heavy metal ions, especially on bismuth-based materials. Polyoxometalates have been received lots of attention and widely applied in many fields. However, the bismuth-containing polyoxometalate has never been reported for the determination of heavy metals. In this study, Na9[BiW9O33]·16H2O (BiW9) was utilized to construct an electrochemical sensor towards the simultaneous detection of Cd(II) and Pb(II). The prepared bismuth-containing polyoxometalate BiW9 was characterized by X-ray diffraction and Fourier transform infrared spectroscopy, which was then casted onto the surface of glassy carbon electrode (GCE) to test the electrochemical behavior by square wave anodic stripping voltammetry. The results showed that BiW9/GCE possesses a good electroanalytical performance for the simultaneous determination of Cd(II) and Pb(II) with wide linear ranges and low detection limits. Moreover, the sensor shows good selectivity, repeatability, reproducibility and stability, and owns broad application prospects in the detection of practical water samples. The proposed bismuth-based polyoxometalate fabricated electrochemical sensor exhibits good performance towards the heavy metal ions detection, which may benefit the further application in practical fields.