Copper Selective Polymeric Extractant Synthesized by Ring-Opening Metathesis Polymerization

Area of Science:

• Polymer Chemistry
• Separation Science
• Coordination Chemistry

Background:

• Developing selective materials for metal ion separation is crucial for purification processes.
• Picolinic acid functionalities are known to chelate metal ions.
• Ring-opening metathesis polymerization (ROMP) offers a versatile route to novel polymer architectures.

Purpose of the Study:

• To synthesize novel polymers with pendant picolinic acid functionalities using ROMP.
• To evaluate the selectivity of these polymers for copper(II) ions (Cu²⁺) against other divalent metal cations.
• To assess the potential of these polymers in separation-based purification protocols, including radioisotope purification.

Main Methods:

• Synthesis of novel polymers via ring-opening metathesis polymerization (ROMP).
• Preparation of the corresponding monomer bearing picolinic acid functionalities.
• Metal ion selectivity studies using pH-dependent liquid-liquid and solid-liquid extraction.
• Evaluation of selectivity in mock purification protocols, specifically for Cu²⁺ over Ni²⁺.

Main Results:

• The synthesized polymers and monomer demonstrated selective binding for Cu²⁺ over various other divalent metal cations.
• High selectivity for Cu²⁺ was observed even in the presence of a significant excess of Ni²⁺.
• Separation factors reaching as high as 290 were achieved for Cu²⁺ extraction from solutions with a 100-fold excess of Ni²⁺.

Conclusions:

• Novel polymers with pendant picolinic acid groups synthesized via ROMP are effective for selective Cu²⁺ separation.
• The polymer system exhibits excellent selectivity for Cu²⁺, relevant for applications such as Cu radioisotope purification.
• These findings highlight the potential of functionalized polymers in advanced separation technologies.