Ion-imprinted nanocellulose aerogel with comprehensive optimized performance for uranium extraction from seawater

Abstract

Significantly abundant uranium resources in seawater are considered promising alternatives to terrestrial uranium reserves. The adsorption capacity and speed, binding selectivity, mechanical properties, and antibiofouling ability are the most important features for practical uranium adsorbent applications. Herein, a new nanocellulose aerogel, which contains specific binding spatial structures for uranyl ions, designated as I-CNF aerogel, is fabricated by combining ion-imprinting and chemical cross-linking strategies. The ion-imprinted and chemically stabilized functional sites endow the I-CNF aerogel with robust binding affinity and selectivity for uranyl ions. The ordered lamellar structure, porosity, and high hydrophilicity together facilitate uranyl ion access to the functional sites in the adsorbent and endow the adsorbent with a high uranium adsorption capacity. Furthermore, owing to the chemical cross-linking process and the generated Schiff base groups, the adsorbent exhibits high mechanical strength, excellent reusability, and effective antibiofouling activity. Benefitting from these optimized properties, I-CNF aerogel demonstrates a high uranium extraction capacity of 9.46 mg g−1 with an ultrahigh selectivity of 19.01 to uranium against vanadium in natural seawater, making it a highly potential candidate for practical uranium extraction in natural seawater.