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Ternary Complex Formation and Extraction Modeling in Malonate-Buffered Trivalent Actinide-Lanthanide Separations
Joseph L Lapka1, Sandrine Wahu1, Sergey Sinkov2
1Chemistry Department , Washington State University , Pullman , Washington 99164 , United States.
Inorganic Chemistry
|May 24, 2019
Summary
The Advanced TALSPEAK system effectively forms a stable ternary complex with malonate, HEDTA, and trivalent ions, improving metal separation predictability. This malonate-buffered system offers advantages over conventional TALSPEAK for complex chemical separations.
Area of Science:
- Coordination Chemistry
- Separation Science
- Radiochemistry
Background:
- Conventional TALSPEAK systems face challenges with complex metal ion interactions.
- Understanding ternary complex formation is crucial for optimizing separation processes.
Purpose of the Study:
- To investigate the formation of an aqueous ternary complex in the malonate-based Advanced TALSPEAK system.
- To refine stability constants and model metal speciation for improved separation efficiency.
Main Methods:
- Solvent extraction and optical spectroscopy were employed to study complex formation.
- A solvent extraction model was developed using experimentally determined stability constants.
Main Results:
- Spectroscopy confirmed the presence of a ternary complex involving malonate, HEDTA, and trivalent americium/lanthanide ions.
- Stability constants determined by spectroscopy and modeling showed good agreement.
- Calculated metal distribution ratios correlated well with experimental data.
Conclusions:
- Malonate-buffered Advanced TALSPEAK offers a simpler and more predictable system for metal ion separation compared to conventional TALSPEAK.
- The developed model accurately predicts metal speciation and extraction behavior.
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