In-situ synthesis of bi-metallic metal organic Framework/Polyaniline nanocomposites as ultrasensitive and selective electrodes for electrochemical detection of heavy metal ions

Due to the toxicity of heavy metal ions which impacts on public health and the environment, the development of effective methods of detection has assumed a high priority. In this study, we have established an electrochemical sensor based on a CoCu-MOF/polyaniline (CoCu-MOF/PANI) sensing electrode that can simultaneously detect Pb 2+ and Cd 2+ in water samples. The CoCu-MOF/PANI composite was prepared by a one-step in situ polymerization method and characterized by scanning electron microscopy (SEM), X-ray diffraction (XRD), X-ray photoelectron spectroscopy (XPS) and Fourier transform infrared spectroscopy (FTIR). The Pb 2+ and Cd 2+ content was detected by differential pulse voltammetry (DPV) at an optimized pH (4.5). The proposed electrochemical sensor has achieved simultaneous Pb 2+ and Cd 2+ detection down to 0.39 ug/L (Pb 2+ ) and 0.61 ug/L (Cd 2+ ). Anti-interference and reproducibility experiments have been conducted. In spiking experiments, the recovery of Pb 2+ and Cd 2+ in water samples ranged from 98.6% to 102.13%, indicating effective targeted electrochemical sensing. This work has delivered a functional design of CoCu-MOF/PANI materials, and established an efficient methodology for heavy metal ion detection.