Bipolar Ion Exchange Sheet with Nanoparticle Coatings
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Solution Overview
Problem
Bipolar ion exchange sheets exhibit low ion selectivity and high membrane resistance, leading to reduced water decomposition efficiency and the need for high voltage for regeneration, which can cause heat generation.
Innovation Solution
A bipolar ion exchange sheet comprising a cation exchange membrane bonded with an anion exchange membrane, both having coating layers with metal hydroxide nanoparticles, and an optional water decomposition catalyst layer, fabricated using extruded films with specific thicknesses and binder content to enhance ion exchange and mechanical properties.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If conventional cation or anion exchange resin powders with polyethylene binders are used to produce bipolar ion exchange sheets, then ion adsorption characteristics are improved, but ion selectivity decreases and membrane resistance increases, reducing water decomposition efficiency
Solution Approach 1:
The patent uses composite materials by combining cation exchange resin particles and anion exchange resin particles within a porous substrate structure. This composite approach allows the membrane to simultaneously achieve good ion adsorption characteristics while maintaining high ion selectivity and low membrane resistance, resolving the contradiction between reliability and productivity
Solution Approach 2:
The patent employs a porous substrate that provides a three-dimensional network structure for supporting ion exchange resins. This porous structure increases the surface area for ion exchange reactions, improves ion transport pathways, and reduces membrane resistance, thereby enhancing water decomposition efficiency while maintaining ion adsorption capabilities
2Ease of operation
If high voltage is applied to regenerate bipolar ion exchange sheets, then ion desorption is achieved, but heat generation increases
Solution Approach 1:
The patent modifies the electrical parameters by enabling effective ion desorption at lower voltages through the optimized bipolar structure. The combination of cation and anion exchange layers with proper thickness ratios and the porous substrate structure reduces the electrical resistance, allowing regeneration to occur at lower voltages and thus reducing heat generation while maintaining ion desorption capability
3Productivity
If membrane resistance is reduced to improve water decomposition efficiency, then lower operating voltage is needed, but mechanical strength may be compromised
Solution Approach 1:
The porous substrate provides a rigid three-dimensional framework that maintains mechanical strength while creating efficient ion transport pathways. The porosity allows for low membrane resistance and high ion conductivity, while the structural integrity of the substrate ensures adequate mechanical strength, resolving the contradiction between productivity and strength
Solution Approach 2:
The composite structure combining ion exchange resins with a porous substrate creates a material that leverages the electrical conductivity of resins and the mechanical strength of the substrate. This composite approach allows simultaneous optimization of water decomposition efficiency and mechanical properties
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 solution achieves low membrane resistance, increased water decomposition efficiency, and improved ion adsorption and desorption characteristics at lower voltages, with enhanced mechanical and thermal stability, suitable for various industrial water treatments.
Implementation Method 1
a cation exchange membrane including a cation adsorption sheet and a cation exchange coating layer formed on one surface of the cation adsorption sheet; and an anion exchange membrane including an anion adsorption sheet and an anion exchange coating layer formed on one surface of the anion adsorption sheet
Implementation Method 2
when current is supplied while cation exchange membranes and anion exchange membranes are bonded to each other, such that cation exchange layers are oriented toward cathodes and anion exchange layers are oriented toward anodes, water molecules are decomposed into hydrogen ions (H+) and hydroxide ions (OH−)
Implementation Method 3
a bipolar ion exchange sheet which may have excellent mechanical properties and low resistance and may improve water decomposition characteristics by adsorbing or desorbing ions in an electrical manner without using chemicals
Data Source
AI summary
The present invention relates to a bipolar ion exchange sheet and a manufacturing method therefor, the bipolar ion exchange sheet comprising: a cation exchange film comprising a cation adsorption sheet and a cation exchange coating layer formed on one side of the cation adsorption sheet; and an anion exchange film comprising an anion adsorption sheet and an anion exchange coating layer formed on one side of the anion adsorption sheet, wherein the cation exchange film and the anion exchange film are bonded so that the cation exchange coating layer and the anion exchange coating layer face each other.