Highly selective and sensitive colorimetric chemosensor using PVA/chitosan ion-imprinted nanofibers for copper ion detection and removal

• Published in: Heliyon 2024-08, Vol.10 (15), p.e35193, Article e35193
• Main Authors: Yousefi-Limaee, Nargess, Rouhani, Shohre, Kamandi, Ramtin
• Format: Article
• Language: English
• Subjects: Adsorption; Colorimetric chemosensor; Cu (II)-Imprinted polymer; Naked-eye detection; Nanofiber; PVA/Chitosan
• ISSN: 2405-8440; 2405-8440
• DOI: 10.1016/j.heliyon.2024.e35193

Herein, a highly efficient colorimetric chemosensor incorporating ion-imprinted electrospun nanofiber was developed for the removal and detection of Cu2+ ions. In this regard, PVA/chitosan composites were used as the polymeric matrix, and 1-(2-pyridylazo)-2-naphthol was employed for complex formation. The prepared naked-eye sensor was characterized using Fourier transform infrared spectroscopy, energy-dispersive X-ray spectroscopy, scanning electron microscopy, atomic force microscopy, differential scanning calorimetry, thermogravimetric analysis, and X-ray diffraction analysis, revealing the morphological, structural, and molecular properties of the sensor. The results showed that the colorimetric chemosensor based on copper-imprinted nanofiber (Cu–INF) possesses higher selectivity for Cu2+ compared to interference ions. The selectivity coefficient (k) and relative selectivity coefficient (K′) indicated the selective behavior of Cu–INF in the adsorption of Cu2+ in binary systems including Cu2+/Co2+, Cu2+/Ni2+, and Cu2+/Zn2+. Furthermore, the ion-imprinted nanofiber was used for the preconcentration of copper ions, demonstrating a high adsorption capacity of 128.205 mg g−1 for Cu2+. The equilibrium adsorption isotherm and adsorption kinetics of Cu2+ on Cu–INF followed the Freundlich adsorption isotherm and a pseudo-second-order model, respectively. The developed sensor exhibited a linear detection range of 5 × 10−8 - 2 × 10−7 M with a limit of detection (LOD) of 1.07 × 10−8 M for copper ions. The results indicated satisfactory adsorption and successful detection of Cu2+ at trace concentrations.