Enhancing U(VI) adsorptive removal via amidoximed polyacrylonitrile nanofibers with hierarchical porous structure

Abstract

In this study, hierarchical porous polyacrylonitrile nanofibers were fabricated via electrospinning zeolitic imidazolate framework-8 (ZIF-8) and polyacrylonitrile (PAN), followed by tannic acid (TA) etching and amidoximation (denoted as p-PAN-AO). The as-prepared p-PAN-AO was utilized to remove radioactive U(VI) from sewage water and simulated seawater. The influence of uranium adsorption on p-PAN-AO was investigated as a function of uranium concentration, pH, and time. Adsorption kinetic experiments indicated that the pseudo-second-order kinetic model was fitted better than the pseudo-first-order model. Benefiting from amidoximation and hierarchical porous structure, the nanoadsorbent exhibited a high U(VI) adsorption capacity of 412.28 mg/g at 298 K. The thermodynamic analysis manifested a spontaneous and endothermic nature of U(VI) adsorption. The results demonstrated a potential application of the reported materials in nuclear wastewater and environmental cleanup.