Nickle(II) and cobalt(II) ion removal using electrospun β-cyclodextrin/grafted-chitosan nanofibers as efficient molecular filters
Zahra Norouzi, Hamidreza Abdouss, Majid Abdouss
Abstract
Considering the gradual depletion of water resources, developing smart molecular filters targeting heavy metal ion removal is necessary. Herein, β-Cyclodextrin (β-CD) was coupled with chitosan (CS) to yield β-cyclodextrin/grafted-chitosan, which was subsequently electrospun to form nanofibrous membrane (β-CD-g-CS/PVAnfm). The sample was certified using FT-IR, 1H NMR, XRD, SEM, and EDX analyses. β-CD-g-CS/PVAnfm receives the combined features of both CS and β-CD, including size specificity, host-guest complexation properties of β-CD, and the chelation ability of CS, along with the fascinating advantages of nanofibers, which synergistically amplifies ion adsorption. The outstanding features of β-CD-g-CS/PVAnfm as a molecular filter were investigated by measuring the absorbance of Ni(II) and Co(II) ions using atomic absorption spectroscopy. β-CD-g-CS/PVAnfm exhibited remarkable efficacy in absorbing Ni(II) and Co(II) ions, with a maximum adsorption capacity of 154 mg/g and 160 mg/g, respectively. Isotherm studies revealed the superior fit of Freundlich and Tempkin isotherms for Ni(II) and Co(II) ions, respectively, while kinetic data align with the pseudo-second-order model. These results demonstrate the outstanding heavy metal ion removal capacity of β-CD-g-CS/PVAnfm, rendering treated water safe for reuse. While acknowledging techno-economic challenges in electrospinning, we suggest exploring electrospinning in liquid media as a roadmap for future research.