Realizing Direct Uranium Extraction from Seawater Using a Carboxyl-g-C₃N₄/CdS Hydrogel

Area of Science:

• Materials Science
• Environmental Chemistry
• Nanotechnology

Background:

• Photocatalytic reduction of Uranium(VI) is key for uranium recovery.
• Seawater uranium extraction faces challenges from carbonate presence and atmospheric conditions.

Purpose of the Study:

• To design a photoactive hydrogel for efficient uranium extraction from seawater.
• To overcome limitations of carbonate presence and atmospheric conditions in photocatalytic uranium recovery.

Main Methods:

• Fabrication of a carboxyl-functionalized g-C3N4/CdS (CCN/CdS) photoactive hydrogel.
• Testing the hydrogel's photocatalytic U(VI) reduction efficiency under atmospheric conditions with carbonate.
• Evaluating uranium extraction capacity, elution, stability, and recyclability.

Main Results:

• The CCN/CdS hydrogel achieved >80% U(VI) reduction in 150 min with carbonate, without electron donors.
• High uranium extraction capacity of >434.5 mg g⁻¹ was observed.
• The hydrogel demonstrated excellent stability, recyclability, antifouling properties, and ease of separation.

Conclusions:

• The developed photoactive hydrogel is highly effective for seawater uranium extraction.
• The material's properties make it suitable for practical, large-scale uranium recovery from marine environments.
• Successful uranium extraction from real seawater confirms the hydrogel's applicability.