Colorimetric chemosensor for Cu(II) from electrospun nanofibrous mat mixed with 5‐methoxy‐salicylaldehyde azine

Abstract

AbstractThe condensation product of 5‐methoxy‐salicylaldehyde with hydrazine hydrate (referred to below as compound 1) was used as a ligand in a cellulose acetate electrospun nanofibrous mat to determine copper ions in aqueous solutions. The electrospun nanofibrous mats, based on cellulose acetate mixed with compound 1, were constructed using an electrospinning method and had a diameter of 260 nm. The sensing nanofibrous mat exhibited a sensitive and selective response for Cu(II) ions over a linear concentration range of 1‐30 µM in a 0.1 M HEPES buffer (pH 7.4) using a colorimeter. The detection limit of the method was 1.04 µM lower than the maximum level of Cu(II) in drinking water (16 µM, as determined by the US Environmental Protection Agency). Additionally, it exhibited high selectivity for Cu(II) ions over 13 other cations. The sensing nanofibrous mat was fully reversible for ethylenediamine tetraacetic acid treatment cycles. Preliminary results indicated the sensitivity and selectivity of the nanofibrous mat for detecting Cu(II) ions by naked‐eye detection from yellow to orange. The reaction product of compound 1 and the Cu(II) ion was studied using X‐ray absorption spectroscopy. The Cu‐coordination number was approximately 5.023 ± 1.42, and the Cu–N distance (R) was 1.986 Å. The nanofibrous mat demonstrated a convenient and straightforward Cu(II) ion‐detection technique in both wastewater and water environments.