Engineering Mass-Transfer-Optimized Lamellar Structures for Enhanced Uranium Extraction From Seawater

Area of Science:

• Materials Science
• Environmental Science
• Nuclear Engineering

Background:

• Terrestrial uranium resources are dwindling, necessitating alternative extraction methods.
• Polyamidoxime (PAO)-based adsorbents show potential for uranium extraction from seawater (UES) due to their favorable properties.

Purpose of the Study:

• To synthesize and characterize novel monolithic aerogels (PAOHNs) composed of PAO and hydroxyapatite nanowires (HAPNWs) for efficient UES.
• To optimize aerogel structure and adsorption properties through material design and computational modeling.

Main Methods:

• Directional freeze casting was employed to synthesize PAOHNs aerogels with varying PAO-to-HAPNWs ratios.
• COMSOL Multiphysics simulations were used to optimize structural parameters like pore structure and channel size.
• Adsorption performance was evaluated using cyclic filtration in natural seawater.

Main Results:

• Aerogel morphology evolved from a porous network (PAOHNs-1) to a vertically aligned lamellar structure (PAOHNs-3) with increasing HAPNWs content.
• PAOHNs-3 exhibited superior diffusion pathways and a higher overall adsorption rate for uranyl ions compared to PAOHNs-1.
• PAOHNs-3 achieved a uranium extraction capacity of 12.5 mg g⁻¹ after 20 days of cyclic filtration in natural seawater.

Conclusions:

• The PAOHNs aerogels, particularly PAOHNs-3, demonstrate significant potential for efficient and long-term uranium recovery from seawater.
• Integrating computational modeling with material synthesis provides a pathway for rational design of advanced UES adsorbents.
• This approach supports sustainable nuclear energy development by addressing uranium resource limitations.