Ligand-Assisted Chromatography for High-Purity REE Separation

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Solution Overview

Problem

Current methods for separating rare earth elements (REE) are inefficient, generate toxic waste, and are not environmentally sustainable, particularly due to the difficulty in separating REE with similar physicochemical properties, which limits their large-scale production and processing in countries like the U.S. with strict environmental regulations.

Innovation Solution

A method for designing an efficient chromatographic separation process using an algorithm that analyzes feed mixtures, selects appropriate sorbents and displacers, and optimizes separation parameters to achieve high productivity and purity, incorporating dimensionless group analysis for predicting optimal operating conditions in ligand-assisted displacement chromatography.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Productivity

If conventional liquid-liquid extraction methods are used to separate REE, then separation can be achieved, but large amounts of toxic waste are generated and the process is inefficient

Engineering Contradiction:
Improveseparation efficiencyVSAvoidtoxic waste generation
Core Design Contradiction:
ProductivityVSObject-generated harmful factors

Solution Approach 1:

The patent replaces the conventional mechanical liquid-liquid extraction system with a chromatographic separation system using ligand-functionalized sorbents. This substitution eliminates the need for large volumes of toxic solvents and extractants, thereby reducing harmful waste generation while maintaining separation efficiency through selective ligand-receptor interactions.

Inventive Principle:
Principle #28Mechanics substitution (Replace mechanical system)

Solution Approach 2:

The patent changes the fundamental separation parameter from bulk liquid-liquid partitioning to surface-bound ligand-selective binding. By functionalizing sorbent surfaces with specific ligands (e.g., phosphonic acids, carboxylic acids), the separation mechanism shifts to selective adsorption based on coordination chemistry, improving productivity while minimizing toxic waste.

Inventive Principle:
Principle #35Parameter changes

2Manufacturing precision

If conventional ion exchange or chromatography processes are used, then REE can be separated, but the processes are not effective due to similar physicochemical properties of REE

Engineering Contradiction:
Improveseparation purityVSAvoidseparation effectiveness
Core Design Contradiction:
Manufacturing precisionVSProductivity

Solution Approach 1:

The patent introduces ligands as intermediary molecules that mediate the separation of REE. These ligands (e.g., phosphonic acids, carboxylic acids, hydroxamic acids) act as selective intermediaries that bind to specific REE ions through coordination chemistry, enabling high-purity separation despite the similar physicochemical properties of the rare earth elements themselves.

Inventive Principle:
Principle #24Intermediary (Mediator)

Solution Approach 2:

The patent employs composite sorbent materials combining inert support structures (e.g., silica, polymer beads) with functional ligand layers. This composite approach provides both the mechanical stability needed for industrial operation and the selective chemical functionality required for high-purity REE separation, resolving the contradiction between manufacturing precision and productivity.

Inventive Principle:
Principle #40Composite materials

3Productivity

If ligand-assisted displacement chromatography is used, then separation productivity can be improved, but the separation mechanism is not well understood and requires trial and error design

Engineering Contradiction:
Improvesorbent productivityVSAvoidprocess design complexity
Core Design Contradiction:
ProductivityVSDevice complexity

Solution Approach 1:

The patent incorporates systematic characterization methods that provide feedback on ligand-sorbent-receptor interactions. By measuring binding constants, selectivity factors, and kinetic parameters through controlled experiments, the design process transitions from trial-and-error to a feedback-driven optimization approach, reducing design complexity while maintaining high productivity.

Inventive Principle:
Principle #23Feedback

Solution Approach 2:

The patent performs preliminary characterization of ligand-sorbent systems before full-scale separation operations. By pre-determining optimal ligand types, functionalization densities, and operating conditions through analytical testing, the system eliminates the need for extensive trial-and-error during actual production, thereby reducing design complexity while preserving high sorbent productivity.

Inventive Principle:
Principle #10Preliminary action

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 approach enables the efficient separation of REE with high productivity and purity, reducing waste generation and making the process more environmentally sustainable, suitable for large-scale production while adhering to stringent environmental regulations.

Implementation Method 1

Ligand-assisted chromatography separates REE by utilizing complexation reactions between REE and ligands

Methodology Applied
Scientific EffectAdsorption: Adsorption

Implementation Method 2

several commercially available ligands have significant selectivity for REE

Methodology Applied
Scientific EffectComplexation reaction: Chemical Bonding

Data Source

PatentEP3684488B1Method for designing an efficient preparative chromatographic separation process
Publication Date: 2023.12.20 PURDUE RES FOUND
  • EP3684488B1 patent drawingFigure 1A
  • EP3684488B1 patent drawingFigure 1B
  • EP3684488B1 patent drawingFigure 2a~2b

AI summary

The present invention relates to a method for designing an efficient chromatographic separation process for a multicomponent mixture, such as a mixture of rare earth elements (REE), a production mixture from a pharmaceutical manufacturing or biotechnology production process, employing the concept of constant pattern mass transfer zone length (LMTZ,CP) in a non-ideal system having significant spreading of the concentration waves. This present invention can be used for ligand-assisted displacement chromatographic (LAD) as well as conventional displacement chromatographic separation processes. Since this method uses dimensionless groups, it can be used for the design of various scales of separation. This method may also find applications in a continuous process as a "multi-zone LAD process" using multiple columns.