Poly(ε-caprolactone) electrospun nanofibers decorated with copper hexacyanoferrate as an ion exchanger for effective cesium ion removal

Abstract

ABSTRACT In this study, poly(ε-caprolactone) electrospun nanofibers-copper hexacyanoferrate composite ion exchanger (PCL nanofibers–CuHCF) was prepared and used for the cesium ion removal from aqueous solution. The properties and morphology of the synthesized ion exchanger were characterized by Fourier-transform infrared spectroscopy (FTIR), scanning electron microscope (SEM), Brunauer–Emmett–Teller (BET) surface area analysis, X-ray diffraction analysis (XRD), and thermogravimetric analysis (TGA). The cesium ion removal experiments showed that the obtained PCL nanofibers–CuHCF composite exhibited excellent performance for the removal of cesium ions. The influences of several variables such as temperature, pH, and contact time were evaluated in batch experiments. The thermodynamic study indicated a spontaneous and endothermic ion-exchange process. The adsorption isotherm and kinetics of the PCL nanofibers–CuHCF composite were evaluated using the non-linear regression method, indicating monolayer chemisorption of the Langmuir type. The maximum sorption capacities by applying the Langmuir equation were 178.7 mg/g, which is much higher than those of previous reports of some metal-hexacyanoferrates-based composites. PCL nanofibers–CuHCF composite ion exchanger showed excellent selectivity for Cs+ in the presence of competing cations, mainly because of the excellent features of CuHCF.