Blow spinning of pre–acid-activated polyamidoxime nanofibers for efficient uranium adsorption from seawater

Abstract

Polyamidoxime (PAO)-based adsorbents have been extensively studied for uranium (U) extraction from seawater for decades. ‘Hot alkali activation’ treatments are found to significantly improve the U adsorption capacity while inevitably decreasing the strength of PAO-based adsorbents, especially nanofiber (NF) adsorbents. Herein, for the first time, we report that, with proper modification, PAO can be dissolved in acid solution with high solubility, and the pre–acid-activated PAO (PA-PAO) exhibits high uranium capture ability (>1800 mg/g). For better use and collection in large-scale application, PA-PAO is mixed with chitosan (CS) and fabricated to PA-PAO/CS NFs via acidic aqueous solution blow spinning and glutaraldehyde vapor cross-linking. The covalently cross-linked PA-PAO/CS NFs are ready to use without postactivation treatment and achieve highly efficient U capturing performance in U-spiked seawater (913.13 mg/g) and natural seawater (4.91 mg/g, in 10 days), as well as enhanced mechanical stability and antibiofouling (antibacterial) activity. This strategy shows great potential for extraction of U from seawater and contaminated water in a cost-effective, industrial-scale manner.