Extending Silver Nanowire Modified Electrodes to Industrial Zinc Electrolyte for Copper Ion Detection

Real-time and rapid determination of trace copper ion (Cu2+) in the electrolyte of zinc smelting process is urgently needed. However, the complicated composition of the electrolyte, especially the extremely high-concentration of zinc ion (Zn2+) may cause severe interference to the detection of Cu2+. This work describes a facile electrochemical sensor for Cu2+ determination in the electrolyte of zinc smelting plants based on a fluorine-doped tin oxide (FTO) electrode with silver nanowires (AgNWs) and Nafion modification. The AgNWs/Nafion-FTO electrode showed good detection ability with the linear detection range of 0.2-2 mg l-1 Cu2+ in 45 g l-1 Zn2+ solution using differential pulse anodic stripping voltammetry (DPASV) technique. With DPASV technique, Cu2+ can be first reduced and pre-concentrated on the working electrode surface at -0.6 V vs Ag/AgCl for 500 s, after which the deposited Cu metal is oxidized around 0 V vs Ag/AgCl during the stripping step. It has been proved by transmission electron microscopy (TEM) and X-ray photoelectron spectra (XPS) that trace Cu2+ can be adsorbed and reduced on AgNWs in solutions with Zn/Cu ratio up to (2.25-22.5) x 104. The results extend AgNWs modified electrode to the industrial solution, providing a new strategy for detection of trace metal ions in industrial solutions.

Automated summary

This study presents a facile electrochemical sensor for the real-time detection of trace copper ions in the electrolyte of zinc smelting plants. The sensor, based on a modified fluorine-doped tin oxide electrode, demonstrated good detection ability even in the presence of high concentrations of zinc ions. TEM and XPS analysis confirmed the adsorption and reduction of trace copper ions on the silver nanowires, extending the applicability of this sensor to industrial solutions.