Facile synthesis of Ag/PANI/rGO nanocomposite for electrochemical detection of toxic heavy metals in water

Abstract

Electrochemical detection of toxic heavy metal ions is of great significance due to metals harmful impact on the environment. In this work, a reduced graphene oxide (RGO)-supported Ag/PANI nanocomposite electrochemical sensor was synthesized via oxidative polymerization for the detection of lead (Pb2+) and cadmium (Cd2+) ions in ground and surface water. The synthesized nanomaterials were characterized using Fourier transform infrared spectroscopy (FTIR), scanning electron microscopy (SEM), X-ray diffraction (XRD), UV–Vis spectroscopy, electrochemical impedance spectroscopy (EIS), and cyclic voltammetry (CV). The Ag/PANI/RGO-modified glassy carbon electrode (GCE) exhibited higher reversibility compared to other modified electrodes (PANI/GCE and PANI/RGO/GCE) at a scan rate of 50 mV/s, which is attributed to the synergistic interaction among PANI, RGO, and Ag nanoparticles on the electrode surface. Furthermore, the Ag/PANI/RGO nanocomposite sensor was evaluated using the anodic stripping voltammetry technique, yielding excellent linear regression coefficients (R2 = 0.9990 for Pb2+ and R2 = 0.9977 for Cd2+). Under optimized conditions, the Ag/PANI/RGO/GCE sensor demonstrated a wide dynamic linear range (10–100 µg/L), low detection limits (0.57 µg/L for Pb2+ and 0.78 µg/L for Cd2+), high sensitivity, and good recovery rates for the detection of heavy metals in water samples. Overall, the Ag/PANI/RGO/GCE-modified electrode shows strong potential as a reliable sensor for monitoring Pb2+ and Cd2+ contamination in ground and surface water.