Electrochemical Sensors Based on Track-Etched Membranes for Rare Earth Metal Ion Detection

Electrochemical sensors have been developed based on polyethylene terephthalate track-etched membranes (PET TeMs) modified by photograft copolymerization of N-vinylformamide (N-VFA) and trimethylolpropane trimethacrylate (TMPTMA). The modification, structure and properties of the modified PET TeMs were thoroughly characterized using scanning electron microscopy (SEM) and atomic force microscopy (AFM), thermogravimetric analysis (TGA), Fourier-transform infrared (FTIR) spectroscopy, gas permeability measurements and contact angle analysis. Optimal membrane modification was achieved using C = 10% (N-VFA), 60 min of UV irradiation and a UV lamp distance of 10 cm. Furthermore, the modified membranes were implemented in a two-electrode configuration for the determination of Eu3+, Gd3+, La3+ and Ce3+ ions via square-wave anodic stripping voltammetry (SW-ASV). The sensors exhibited a linear detection range from 10−7 M to 10−3 M, with limits of detection of 1.0 × 10−6 M (Eu3+), 6.0 × 10−6 M (Gd3+), 2.0 × 10−4 M (La3+) and 2.5 × 10−5 M (Ce3+). The results demonstrated a significant enhancement in electrochemical response due to the grafted PET TeMs-g-N-PVFA-TMPTMA structure, and the sensor showed practical applicability and consistent performance in detecting rare earth ions in tap water.