Sustainable Mining and Metallurgy

Aim of this study was to establish an electrochemical method for sensitive detection of Cd²⁺ ions in environmental water samples. Utilizing the advantages of Nafion films with three dimensional networks, Nafion-coated bismuth film electrodes on glassy carbon electrode (GCE) were obtained via electrodeposition. The electrodeposition conditions like the Bi(NO₃)₃ concentration, electrodeposition time and the coated Nafion volume were systematically optimized. The electrochemical detection of Cd²⁺ ions was carried out by differential pulse anodic stripping voltammetry (DPASV), and the enrichment potential and time of Cd²⁺ ions, electrolyte type and other conditions were optimized.The experimental results show that the optimum conditions for electrodeposition of Bi are as follows: Bi(NO₃)₃ concentration of 200mg/L, deposition time of 100s, Nafion solution dosage of 3μL; the optimum conditions for the detection of Cd²⁺ by DPV are as follows: the enrichment time is 300s, the enrichment potential is -1.2V, and the ABS electrolyte solution with pH of 4.5 is used.Under the above optimal conditions, the linear range of DPV detection of Cd²⁺ is 2~40μg/L, and the detection limit is 0.5μg/L. The electrochemical sensor was successfully used to analyze the concentration of Cd²⁺ in environmental water samples， holding the recoveries from 98.5% to 112.6% and the relative standard deviation less than 10%. Further detection results from standard addition method confirmed the reliability, which were agreed with the detection data by using ICP-AES method. This study provides a novel approach for exploring electrochemical sensors for Cd²⁺ ions with low cost, high sensitivity and selectivity.