Ionic Liquid-Aqueous Biphasic System for Metal Ion Extraction
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Solution Overview
Problem
Current methods for extracting metal ions from acidic aqueous solutions are often inefficient and require toxic, flammable organic solvents, or use expensive and viscous hydrophobic ionic liquids, which are difficult to handle and have limitations in phase separation and pH compatibility.
Innovation Solution
A biphasic aqueous system comprising an inexpensive hydrophilic ionic liquid and an acid, where the acid plays the role of the organic salt, forming two liquid phases with a pH ≤ 4.7, allowing for efficient metal ion extraction without complex ion mixtures or additional salts, and enabling phase separation through temperature variation.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If organic solvents such as kerosene are used for metal ion extraction from acidic aqueous phase, then extraction efficiency is improved, but toxicity and flammability increase
Solution Approach 1:
The patent replaces expensive, hazardous organic solvents with inexpensive, non-hazardous aqueous solutions containing hydrophilic ionic liquids and inorganic salts. These aqueous systems can be easily disposed of without special safety precautions, eliminating the need for expensive waste treatment infrastructure required for organic solvents.
Solution Approach 2:
The patent changes the fundamental parameter of the extraction medium from organic to aqueous phase. By using hydrophilic ionic liquids with specific hydrophilicity parameters (solubility in water ≥10 g/L) and adjusting salt concentrations, the system achieves effective metal ion extraction while maintaining water as the base solvent, thus eliminating toxicity and flammability issues.
2Productivity
If hydrophobic ionic liquids are used for metal ion extraction, then extraction capability is improved, but viscosity increases and handling becomes complex
Solution Approach 1:
The patent fundamentally changes the hydrophilicity parameter of the ionic liquid from hydrophobic to hydrophilic. By selecting ionic liquids with solubility in water of at least 10 g/L and using inorganic salts with high free enthalpy of hydration, the system achieves low viscosity and easy handling while maintaining effective metal ion extraction capability.
3Object-affected harmful factors
If conventional aqueous two-phase systems are used, then organic solvent use is avoided, but system complexity increases due to multiple salts and acids
Solution Approach 1:
The patent extracts and eliminates unnecessary components from conventional aqueous two-phase systems. Instead of using multiple salts and acids, the system uses only one hydrophilic ionic liquid and one inorganic salt, removing redundant elements while maintaining phase separation and extraction functionality.
Solution Approach 2:
The inorganic salt in the patent serves multiple functions simultaneously: it acts as a phase-forming agent, provides ionic strength for metal ion solubility in acidic medium, and enables phase separation through its high free enthalpy of hydration. This multi-functionality reduces the number of components needed compared to conventional systems.
4Quantity of substance
If existing biphasic aqueous systems with acidic phase are used, then metal ion solubility is improved, but phase separation time increases due to high viscosity
Solution Approach 1:
The patent changes the viscosity parameter by selecting hydrophilic ionic liquids with low viscosity characteristics. The combination of hydrophilic ionic liquid and inorganic salt creates a system with optimized viscosity that enables rapid phase separation (within minutes) while maintaining high metal ion solubility in the acidic aqueous phase.
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 high-yield extraction and separation of metal ions from acidic media, avoiding the use of organic solvents and simplifying the composition, with high extraction efficiency and ease of handling due to the use of less viscous ionic liquids and straightforward phase separation.
Implementation Method 1
aqueous biphasic system ionic liquid-acid... for extracting metal ions
Implementation Method 2
forming two liquid phases with a pH ≤ 4.7, allowing for efficient metal ion extraction... enabling phase separation through temperature variation
Implementation Method 3
enabling phase separation through temperature variation
Implementation Method 4
Metal ions are generally soluble in acidic aqueous solutions
Implementation Method 5
associating two charged species (ionic liquid and inorganic salt)
Data Source
Figure 1~2
Figure 3
AI summary
The application relates to a process for extracting or separating metal ions using a composition comprising: - an ionic liquid of formula C +,-X, in which: - C + is an onium cation comprising at least one hydrocarbon chain R 1 comprising from 6 to 20 carbon atoms, - X P - is an anion of charge p, said ionic liquid having a solubility in water at 20°C of at least 10 g/l, - an acid, and - water, said composition comprising two liquid phases: - a phase enriched in ionic liquid ϕ IL and - a phase enriched in water ϕ w, the pH of which is less than or equal to 4.7, and the uses of the composition for extracting a metal ion from an acidic aqueous medium comprising a metal ion, for separating metal ions from an aqueous medium comprising at least two metal ions or for purifying an acidic aqueous solution comprising a metal ion.