Permselective Membrane Lithium Recovery Device
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Solution Overview
Problem
Existing methods for selectively recovering lithium ions from solutions, such as seawater, are complex, require multiple steps, and suffer from low selectivity and material deterioration, leading to high costs and inefficiencies.
Innovation Solution
A metal ion recovery device utilizing a plate-like permselective membrane with mesh-like electrodes and a porous, electrically conductive current collector, specifically using super lithium ion conductors like Li3N and Li10GeP2S12, to selectively permeate lithium ions, allowing for efficient recovery without the need for extensive equipment or frequent material replacement.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Quantity of substance
If conventional adsorption methods are used to recover lithium ions, then lithium can be extracted from seawater, but the production process becomes complicated requiring two steps of adsorption and desorption
Solution Approach 1:
The patent extracts the lithium ion selective permeation function from the complex adsorption-desorption cycle and concentrates it into a single permselective membrane component. This membrane selectively allows lithium ions to pass through while blocking other metal ions, eliminating the need for separate adsorption and desorption steps and simplifying the overall production process.
Solution Approach 2:
The patent changes the operating mode from chemical adsorption-desorption cycles to physical electrochemical separation. By applying a small voltage across the permselective membrane, lithium ions are selectively transported from the anode chamber to the cathode chamber, enabling continuous recovery without complex cyclic operations.
2Quantity of substance
If conventional adsorption methods are used, then lithium can be recovered from seawater, but the selectivity of lithium adsorption is not high causing co-adsorption of other metals like sodium
Solution Approach 1:
The permselective membrane possesses local quality in the form of lithium-ion-conductive channels or defects within its structure. These localized conductive pathways preferentially allow lithium ions to pass through while blocking other metal ions based on size and charge differences, achieving high selectivity without affecting overall recovery efficiency.
Solution Approach 2:
The patent employs asymmetric structure in the permselective membrane where the pore size, charge distribution, or crystal structure is specifically designed to be asymmetric relative to different ion sizes. This asymmetry creates a selective barrier that allows smaller lithium ions to pass while blocking larger sodium and other metal ions, significantly improving separation precision.
3Quantity of substance
If conventional adsorption materials are used, then lithium can be recovered, but the material involves deterioration in properties during use requiring frequent replacement
Solution Approach 1:
The patent replaces the mechanical/chemical adsorption system with an electrochemical permselective membrane system. The membrane operates through ionic conduction driven by electric potential rather than chemical adsorption, which is less prone to material fatigue and degradation, thereby improving long-term reliability and reducing replacement frequency.
Solution Approach 2:
The permselective membrane is constructed using composite materials that combine lithium-ion-conductive ceramics or polymers with stable supporting structures. This composite design enhances both the selectivity and mechanical/chemical stability of the membrane, allowing it to withstand prolonged operation in seawater environments without significant property deterioration.
4Quantity of substance
If conventional adsorption methods are used, then lithium can be extracted, but it is expensive due to frequent material replacement and complex processes
Solution Approach 1:
The patent extracts the essential lithium separation function from the complex multi-step adsorption-desorption process and concentrates it into a single permselective membrane component. This simplification reduces the number of operational steps, minimizes material replacement needs, and lowers overall production costs while maintaining effective lithium recovery.
Solution Approach 2:
The permselective membrane operates autonomously under a small applied voltage, selectively transporting lithium ions without requiring external chemical reagents or complex operational interventions. This self-service capability reduces operational costs and simplifies manufacturing compared to conventional methods requiring frequent material replacement and complex process control.
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
The device achieves high selectivity and cost-effective lithium ion recovery, even from seawater, with reduced operational complexity and extended material lifespan, while minimizing co-adsorption of other metals like sodium.
Implementation Method 1
a plate-like permselective membrane constituted by an ion conductor of said metal
Implementation Method 2
a mesh-like positive electrode fixed to one main face of said permselective membrane, and a mesh-like negative electrode fixed to the other main face
Data Source
AI summary
Problem is to selectively and inexpensively recover a metal ion in a liquid.Solution is a metal ion recovery device, in which a permselective membrane for selectively permeating Li is used, and on both main faces of the plate-like permselective membrane, a mesh-like negative electrode and a positive electrode are formed, respectively. This structure is provided in a treatment tank, and in the treatment tank, the permselective membrane partitions between a stock solution containing a Li ion, and a recovery solution into which Li is recovered. As the permselective membrane, lithium nitride (Li3N), Li10GeP2S12, (Lax, Liy)TiOz, Li1+x+yAlx(Ti, Ge)2−xSiyP3−yO12, and the like, which are super lithium ion conductors, can be used.