Electrochemical Detection of Cd²⁺ and Pb²⁺ in Wastewater by Amino C-dot-MOF/GCE

Abstract

Carbon dots(C-dots) and metal-organic frameworks (MOFs) have found widespread applications in sensing, energy storage, and catalysis, yet their utilization in electrochemical sensing remains relatively limited. This study focuses on the preparation of C-dots/UiO-66-NH2 as a modified material on glassy carbon electrodes to detect cadmium and lead ions in water using electrochemical methods. The material was created by utilizing m-phenylenediamine as a C-dots source and amino-functionalized zirconium-based metal-organic frameworks, combining these two popular materials. The presence of amino groups in the structure facilitated the complexation with metal ions, providing an effective interface for metal ion adsorption. Under optimized deposition conditions, C-dots/UiO-66-NH2 demonstrated excellent linearity and low detection limits for metal ions (Cd2+ and Pb2+) within the concentration range of 30 to 180 μg/L. The limits of detection (LOD) were LOD(Cd) = 2.16 μg/L and LOD(Pb) = 1.08 μg/L for individual detection, and LOD(Cd) = 2.62 μg/L and LOD(Pb) = 1.36 μg/L for simultaneous detection. These results highlight the suitability of C-dots/UiO-66-NH2 for the determination of Cd2+ and Pb2+ in water. Furthermore, the C-dots/UiO-66-NH2/GCE sensor exhibited robust immunity to interference and maintained detection stability, showcasing its potential for practical applications.