Sequential separation of lanthanides, thorium and uranium using novel solid phase extraction method from high acidic...

Area of Science:

• Materials Science
• Radiochemistry
• Separation Science

Background:

• Nuclear waste contains valuable and hazardous actinides and lanthanides.
• Efficient separation and extraction methods are crucial for nuclear waste management and resource recovery.

Purpose of the Study:

• To develop a novel grafted polymer for selective and sequential separation of lanthanides, thorium, and uranium.
• To characterize the grafted polymer and optimize extraction conditions.
• To evaluate the resin's performance in real-world waste samples.

Main Methods:

• Grafting Merrifield chloromethylated (MCM) resin with octyl(phenyl)-N,N-diisobutylcarbamoyl-methylphosphine oxide (CMPO).
• Characterization using FT-IR, NMR spectroscopy, and elemental analysis.
• Optimization of extraction parameters (e.g., nitric acid concentration) via static and dynamic methods.

Main Results:

• High sorption capacities: 0.960 mmol/g for U(VI), 0.984 mmol/g for Th(IV), 0.488 mmol/g for La(III), and 0.502 mmol/g for Nd(III).
• Fast extraction kinetics (<5 min for 50% extraction) and high reusability (>20 cycles).
• Successful application in extracting Th(IV) from monazite sand and U(VI)/Th(IV) from simulated nuclear spent fuel.

Conclusions:

• The developed MCM-CMPO grafted resin is highly effective for selective and sequential separation of target metal ions from acidic nuclear waste.
• The resin offers excellent sorption capacity, rapid kinetics, and reusability, making it a promising material for nuclear waste treatment.
• The method's reliability and reproducibility are confirmed by analytical data within 3.5% RSD.