Simultaneous determination of Cd2+ and Pb2+ by an electrochemical sensor based on Fe3O4/Bi2O3/C3N4 nanocomposites

The high adsorption capacity of Fe3O4 and C3N4 for heavy metals and the amalgam effect of Bi2O3 were exploited using a Fe3O4/Bi2O3/C3N4-modified glassy carbon electrode (GCE) for the determination of Cd2+ and Pb2+. The electrochemical response performance of the Fe3O4/Bi2O3/C3N4/GCE was studied by square-wave anodic stripping voltammetry. The electrochemical conditions were optimized, including the pH of the buffer solution, content of Fe3O4/Bi2O3/C3N4 on the electrode surface, deposition potential and deposition time. Under optimum conditions, the Fe3O4/Bi2O3/C3N4/GCE sensor shows a linear response from 0.01 μmol/L to 3 μmol/L. The minimum detectable quantity for Cd2+ and Pb2+ are 3 × 10−9 mol/L and 1 × 10−9 mol/L, respectively. Interference studies were carried out. The sensitivity of the Fe3O4/Bi2O3/C3N4/GCE sensor to Cd2+and Pb2+ does not significantly change in the presence of coexisting heavy metal ions. The Fe3O4/Bi2O3/C3N4/GCE sensor exhibits good stability and repeatability. The Fe3O4/Bi2O3/C3N4/GCE sensor was used to detect Cd2+and Pb2+ in river water samples to demonstrate its real-world application.