Ion-Selective Shock Electrodialysis with Scalable Porous Media
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Existing desalination technologies using shock electrodialysis face challenges in scalability and efficiency due to the need for massive parallel channels and complex geometries, limiting their application to small-scale systems.
Innovation Solution
A scalable and continuous water deionization system utilizing a rectangular geometry with a cationic porous medium and cation exchange membrane, where a voltage differential creates a desalination shock within the porous medium, allowing for efficient separation of ions and purification of water by surface conduction and electroosmotic flow.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If microfluidic devices with nanochannels are used for shock electrodialysis, then ion-selective separation efficiency is improved, but device complexity and scalability are worsened due to the need for massive parallel channels
Solution Approach 1:
The patent replaces complex nanochannel arrays with a porous medium having interconnected pores of 0.1-10 μm diameter. The porous structure naturally provides ion-selective pathways through surface charge effects without requiring precise fabrication of individual channels, thereby maintaining separation efficiency while dramatically simplifying device construction and enabling scalability.
Solution Approach 2:
The patent extracts the essential function of ion-selective separation from the complex nanochannel geometry and implements it through the surface charge properties of the porous medium alone. This separation of function from complex structure allows the system to achieve the same ion-selective effect without the need for massively parallel fabricated channels.
2Productivity
If radially symmetric geometry is used for shock electrodialysis, then overlimiting current and desalination efficiency are improved, but ease of manufacture and scale-up are worsened
Solution Approach 1:
The patent segments the radially symmetric device into modular rectangular components including separate porous medium modules, membrane modules, and electrode modules. This segmentation allows each component to be manufactured independently using standard fabrication techniques and then assembled into scalable configurations, maintaining desalination efficiency while greatly improving ease of manufacture.
Solution Approach 2:
The patent transitions from a radially symmetric (2D circular) geometry to a rectangular (1D linear) geometry that can be easily stacked and scaled in the vertical dimension. This dimensional change enables simple linear scaling by adding more rectangular modules in series or parallel, whereas radial geometry would require complex lateral expansion.
3Volume of moving object
If porous media with interconnected pores are used, then compactness and surface conduction are improved, but manufacturing precision and control over pore structure are worsened
Solution Approach 1:
The patent specifies a pore diameter range of 0.1-10 μm that is large enough to be manufactured with conventional porous material techniques (such as sintering or phase separation) while still small enough to provide significant surface area for surface conduction. This parameter optimization balances manufacturing feasibility with the desired compactness and electrochemical performance.
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 system achieves high desalination efficiency, with over 99.99% removal of salts and additional purification capabilities, including filtration and disinfection, while being amenable to large-scale applications.
Implementation Method 1
electroosmotic flow dominates transport
Implementation Method 2
surface conduction takes over
Implementation Method 3
the depletion on one side and enrichment on the other could be described as a shock
Data Source
AI summary
Ion-selective separation by shock electrodialysis is performed by applying a voltage differential between electrodes across a porous medium to selectively draw a first species in a liquid toward at least one of the electrodes to a greater degree than a degree to which a second species in the liquid is drawn toward the same electrode. The voltage differential creates a shock in the charged-species concentration in the bulk volume of the liquid within pore channels of the porous medium, wherein the concentration of the first species in a depleted zone of the liquid bulk volume between the shock and the ion-selective boundary is substantially lower than the concentration of the second species in the liquid bulk volume between the shock and the first electrode. A dilute stream including the second species is extracted from the depleted zone separate from a concentrated stream including the first species.