Actinium Isolation via Anion Exchange Chromatography
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Current methods for isolating Actinium-227 from radium and thorium mixtures are not optimal in terms of yield and separation efficiency, often leading to contamination and loss of radionuclides due to the elution of thorium and actinium during long-term use, and the degradation of chemical purity.
Innovation Solution
A method involving the use of an anion exchanger based on styrene cross-linked with divinylbenzene in a nitrate cycle, followed by a purification column with a polymeric matrix containing a covalently bound complexing agent, allows for the separation and recycling of radium, and the efficient isolation of actinium and thorium through controlled elution with nitric acid and methanol solutions.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Manufacturing precision
If ion-exchange column chromatography using anion exchanger MP1 in nitrate and chloride cycle is used, then carrier-free actinium can be obtained, but the extraction agent can be washed out from the sorption bed which leads to degradation of sorption efficiency and chemical purity
Solution Approach 1:
The patent applies local quality by using different stationary phases with specific properties for different separation needs. The anion exchanger with quaternary ammonium groups is specifically designed to retain actinium and thorium anion complexes while allowing other substances to pass through, creating localized chemical environment optimization for high purity separation.
Solution Approach 2:
The patent employs parameter changes by systematically varying the composition and concentration of eluent solutions (different molarities of HNO3, HCl, and their combinations) to control the elution sequence and achieve complete separation of actinium from thorium and other impurities, thereby maintaining both purity and sorption efficiency.
2Manufacturing precision
If anion exchanger based on styrene cross-linked with divinylbenzene in nitrate cycle is used, then actinium can be separated, but thorium and actinium are eluted during long-term use causing loss of radionuclides
Solution Approach 1:
The patent applies preliminary action by performing a specific conditioning procedure before actual separation. The column is pre-treated with 6M HNO3 followed by 0.1M HCl to establish optimal retention properties, ensuring that the stationary phase is in the correct state to prevent unwanted elution of thorium and actinium during long-term operation.
Solution Approach 2:
The patent uses parameter changes by optimizing the eluent composition and flow conditions to maintain stable retention of thorium and actinium. By carefully controlling the acidity and composition of mobile phases, the patent prevents degradation of separation performance over time while maintaining high separation efficiency.
3Manufacturing precision
If extraction chromatography with stationary phase impregnated by extraction agent is used, then actinium separation can be achieved, but the extraction agent washes out leading to degradation of sorption efficiency and chemical purity
Solution Approach 1:
The patent applies composite materials by combining the anion exchanger stationary phase with specific eluent compositions. This composite approach creates a synergistic system where the quaternary ammonium groups on the styrene-divinylbenzene matrix work together with the controlled chemical environment to achieve both high purity separation and stable retention, preventing agent washout.
Solution Approach 2:
The patent uses local quality by creating specific chemical microenvironments within the column through carefully controlled eluent composition. The localized chemical conditions optimize the interaction between the stationary phase and radionuclides, maintaining both purity and retention efficiency throughout the column's operational life.
Applied Scientific Principles
This section explains which scientific principles are used to turn an abstract innovation direction into a practical engineering solution.
Function Achieved in This Case
This method achieves reliable and efficient separation of actinium and thorium, minimizing contamination and maintaining chemical purity, enabling the production of high-purity Actinium-227 suitable for nuclear medicine and industrial applications.
Implementation Method 1
anion exchanger based on styrene cross-linked with divinylbenzene in a nitrate cycle
Implementation Method 2
purification column with a polymeric matrix containing a covalently bound complexing agent
Data Source
Figure 1~2
Figure 3~4
Figure 5a~6
AI summary
The present invention provides a method for isolation of Ac from a mixture comprising radium, actinium and thorium comprising the following steps: a) a mixture of Ra/Ac/Th is loaded onto a separation column containing an anion exchanger based on a styrene cross-linked with divinylbenzene, wherein the content of the cross-linking agent is in the range of 5 to 50 %, preferably 8 to 16 %, in nitrate cycle, and eluted with a solution containing a mixture of 0.6 - 0.8M aqueous solution of nitric acid and methanol in volume ratio of nitric acid solution : methanol = 30 : 70 to 10 : 90, b) the eluate from the separation column is lead through the purification column containing an anion exchanger based on styrene cross-linked with divinylbenzene, wherein the content of the cross-linking agent is in the range of 5 to 50 %, preferably 8 to 16 %, in nitrate cycle, and eluted with a solution containing a mixture of 0.6 - 0.8M aqueous solution of nitric acid and methanol in volume ratio of nitric acid solution : methanol = 30 : 70 to 10 : 90, c) the eluate from step b), containing 226Ra, is isolated, preferably for recycling for repeated irradiation, d) Ac and/or Th is washed out from the separation and the purification column by elution solution containing 5 to 10M mineral acid and optionally at least one complexing agent, preferably the mineral acid is HNO3 and/or HCl.