Ion-Selective Electrodes for Capacitive Deionization
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Conventional capacitive deionization processes lack selectivity for multivalent ions, which are corrosive and contribute to fouling and scaling, and rely on organic solvents that can contaminate de-ionized water.
Innovation Solution
Development of ion-selective polymer coated electrodes using a water-based process, incorporating crosslinkable hydrophilic polymers and ion-exchange materials, allowing for selective removal of monovalent and multivalent ions through scalable flow coating methods without organic solvents.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If conventional capacitive deionization processes are used, then salt removal is achieved, but selectivity for multivalent ions is lacking and organic solvent contamination occurs
Solution Approach 1:
The patent changes the chemical composition parameters of the electrode coating by using water-based slurries with crosslinkable hydrophilic polymers and ion-exchange materials instead of organic solvent-based coatings. This parameter change enables selective removal of multivalent ions through the functional groups in the polymer and ion-exchange material while eliminating organic solvent contamination.
Solution Approach 2:
The patent creates a composite coating material combining crosslinkable hydrophilic polymers (such as polyvinyl alcohol), crosslinkers (such as glutaraldehyde), and ion-exchange materials. This composite structure provides both the selectivity for multivalent ions through ion-exchange mechanisms and the water-based processing capability, resolving the contradiction between selectivity and contamination.
2Productivity
If ion-exchange membranes are placed in front of electrodes, then salt removal and charge efficiency improve, but device complexity increases
Solution Approach 1:
The patent merges the functions of ion-exchange membranes and electrode coatings by incorporating ion-exchange materials directly into the electrode coating formulation. The coating itself becomes ion-selective, eliminating the need for separate ion-exchange membrane layers while maintaining charge efficiency and reducing device complexity.
Solution Approach 2:
The patent applies ion-exchange functionality locally at the electrode surface through the coating, rather than requiring bulk ion-exchange membranes. The coating provides localized ion-selective properties at the critical electrode-solution interface, achieving high charge efficiency without the complexity of membrane integration.
3Ease of manufacture
If flow coating methods are used for electrode fabrication, then manufacturing scalability improves, but coating uniformity may be compromised
Solution Approach 1:
The patent prepares the coating slurry in advance with optimized viscosity and composition characteristics before application. The slurry is formulated with specific solvent content and particle size distribution to ensure uniform flow and deposition during the flow coating process, maintaining coating uniformity while enabling scalable manufacturing.
Solution Approach 2:
The patent optimizes the flow coating process parameters dynamically, including coating speed, slurry flow rate, and substrate movement velocity. By adjusting these dynamic parameters, the process achieves both high scalability and consistent coating uniformity across different production scales.
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 ion-selective electrodes demonstrate enhanced salt removal and charge efficiency, with improved selectivity and long-term stability, reducing contamination risks and environmental impact.
Implementation Method 1
CDI is an emerging desalination technology that utilizes porous electrodes charged with a low electric potential to remove ionic species from aqueous solution through electrosorption. The electric field drives ions to the electrodes resulting in a stream of deionized water.
Implementation Method 2
depositing an slurry onto a substrate, wherein the slurry comprises a porous material, a first crosslinkable hydrophilic polymer, and a crosslinker for the first crosslinkable hydrophilic polymer; annealing the slurry deposited on the substrate to create a crosslinked porous layer on the substrate
Implementation Method 3
depositing an solution comprising an ion-exchange material, a second crosslinkable hydrophilic polymer, and a crosslinker for the second crosslinkable hydrophilic polymer onto the crosslinked porous layer
Data Source
AI summary
A method of forming an electrode for capacitive deionization includes depositing an slurry onto a substrate, wherein the slurry comprises a porous material, a first crosslinkable hydrophilic polymer, and a crosslinker for the first crosslinkable hydrophilic polymer; annealing the slurry deposited on the substrate to create a crosslinked porous layer on the substrate; depositing an solution comprising an ion-exchange material, a second crosslinkable hydrophilic polymer, and a crosslinker for the second crosslinkable hydrophilic polymer onto the crosslinked porous layer; and optionally annealing and/or drying the solution on the crosslinked porous layer.