Electrochemical determination of Cd²⁺ using an NH₂-UiO-67/carbon black composite modified electrode

The discharge of heavy metal ions from industrial waste poses a serious threat to the ecological environment and human health, necessitating the urgent development of efficient and sensitive detection methods. To this end, in this study, an amino-functionalized zirconium-based metal-organic framework (NH₂-UiO-67) was composited with highly conductive carbon black (CB) to prepare a novel NH₂-UiO-67/CB composite nanomaterial, which was subsequently employed to construct an electrochemical sensor for the precise detection of cadmium ions (Cd²⁺) in water. This composite material combines the excellent adsorption and enrichment capability of NH₂-UiO-67 towards Cd²⁺ with the three-dimensional conductive network of CB, and their synergistic effect significantly enhances the electron transfer efficiency and electrochemical response signal at the electrode interface. Differential pulse anodic stripping voltammetry (DPASV) was employed for the quantitative analysis of Cd²⁺. The results demonstrated that under optimized experimental conditions, the sensor exhibited a detection sensitivity of 5.18 μA/μM, a linear range of 0.05-13 μM, and a limit of detection as low as 6.4 nM. Furthermore, the sensor displayed favorable stability, selectivity, and anti-interference capability. When applied to spike recovery experiments in real water samples, the recoveries ranged from 96.17 to 101.7% with relative standard deviations (RSD) of 1.21-4.96%. In summary, this study provides a highly efficient and feasible electrochemical sensing platform for the on-site rapid detection of trace heavy metal ions in the environment, demonstrating broad application prospects.