Chromium-Benzenedicarboxylates Metal Organic Framework for Supersensitive and Selective Electrochemical Sensor of Toxic Cd2+, Pb2+, and Hg2+ Metal Ions: Study of their Interactive Mechanism

Abstract

Voltammetric determination of toxic Cd2+, Pb2+, and Hg2+ metal ions using Cr-BDC/GCE (chromium-benzenedicarboxylates/ Glassy Carbon Electrode) electrochemical sensor has been investigated. Cr-BDC (chromium-benzenedicarboxylate ) metal–organic framework was synthesized by using the facile hydrothermal technique and its efficacy investigated using P-XRD, FTIR, RAMAN, AFM, FE-SEM, and BET, while the electrochemical performance was investigated by CV and EIS technique. The determination capability of Cr-BDC/GCE as an electrochemical sensor has been investigated by DPASV technique. Effective Voltammetric parameters such as pH of buffer solution, pre-accumulation potential, and pre-accumulation time have been optimized to enhance the sensitivity, selectivity, LOD, repeatability, reproducibility, and stability of the sensor. The proposed Cr-BDC/GCE electrochemical sensor exhibits a sensitivity of 16.55, 3.45, and 3.33 μA M−1 and LOD of 0.186, 0.116, and 0.124 nM for Cd2+, Pb2+ and Hg2+ ions, respectively. Moreover, the sensor exhibited good selectivity, reproducibility, repeatability and stability. The sensor also exhibited good recovery and low RSD values for actual tap water samples. Interaction mechanism of Heavy Metal Ions with the Cr-BDC/GCE evidenced by CV and FTIR confirms the surface adsorption-controlled reaction. These findings suggest that the Cr-BDC/GCE platform is well-suited to serve as a next-generation electrochemical sensor for detecting alcohol, ketone, hydrocarbons, medicines, etc.