Wrinkled Layered Sulfide With Tunable Channels Unlocks Precision in Rare Earth Extraction From Radioactive Wastewater

Area of Science:

• Materials Science
• Inorganic Chemistry
• Environmental Science

Background:

• Rare earth elements (REEs) are critical for modern technologies.
• Efficient and selective methods for REE separation and purification are needed, especially for environmental remediation.
• Existing ion exchange methods often require energy-intensive dehydration and lack channel rigidity.

Purpose of the Study:

• To develop a novel crystalline material for enhanced rare earth element (REE) ion exchange.
• To investigate the structural features contributing to improved ion exchange performance.
• To evaluate the material's efficiency, kinetics, capacity, stability, and selectivity for REE removal from aqueous solutions.

Main Methods:

• Synthesis of [(CH3)2NH2]2Ga2Sb2S7 (GaSbS-1) with wrinkled layers and dimensionally adjustable channels.
• Characterization of the material's crystal structure and ion exchange properties.
• Performance evaluation for REE3+ (Y3+, La3+-Lu3+) uptake, including kinetics, capacity, selectivity, and stability across a wide pH range.
• Testing in simulated and real aqueous environments, including seawater and radioactive wastewater.

Main Results:

• GaSbS-1 exhibits high REE3+ ion exchange performance due to its unique wrinkled layer stacking and rigid channels.
• Remarkable kinetics (97.14%-99.40% removal within 5 min) and high capacities (up to 143 mg g-1) were achieved for various REE3+ ions.
• The material demonstrates excellent structural stability (pH 2-12), high selectivity for REE3+ over competing ions, and robust performance in real water matrices.
• Efficient removal (>90%) of REE3+ from seawater and effective purification of REE-contaminated radioactive wastewater were achieved.

Conclusions:

• GaSbS-1 represents a significant advancement in REE ion exchange materials, overcoming limitations of traditional methods.
• Its tunable channel structure and inherent properties facilitate rapid, selective, and high-capacity REE separation.
• The material shows great promise for practical applications in environmental remediation, particularly for purifying REE-contaminated radioactive wastewater.