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

Abstract

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) × 104. The results extend AgNWs modified electrode to the industrial solution, providing a new strategy for detection of trace metal ions in industrial solutions.