PVC-Reinforced Bipolar Membrane for High-Temperature Adhesion
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Solution Overview
Problem
Existing bipolar membranes face challenges in maintaining adhesiveness between cation-exchange and anion-exchange membranes, especially under high-temperature conditions, leading to decreased current efficiency and membrane stability.
Innovation Solution
A bipolar membrane is developed with a cation-exchange membrane supported by a polyolefin reinforcing member containing 15-35% polyvinyl chloride, enhancing adhesiveness by using polyvinyl chloride's high affinity and compatibility with polar solvents, ensuring the membranes remain adhered even under high temperatures.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If chlorinated polyolefin is used to improve adhesiveness between membranes, then adhesiveness and stability are improved, but current efficiency deteriorates
Solution Approach 1:
The invention changes the chemical composition parameters of the cation-exchange membrane by incorporating polyvinyl chloride at 15-35% by mass, replacing or supplementing chlorinated polyolefin. This parameter change maintains adhesiveness while improving current efficiency, as evidenced by gluconic acid leakage ratio being not more than 1.0% at 60°C
Solution Approach 2:
The invention creates a composite membrane structure by combining polyvinyl chloride with cation-exchange resin components. This composite approach allows the membrane to simultaneously achieve strong adhesiveness (preventing peeling under high temperature and extended electrodialysis) and high current efficiency (low gluconic acid leakage), resolving the contradiction between reliability and productivity
2Productivity
If electrodialysis is executed for extended periods or under high-temperature conditions, then production capacity increases, but membrane peeling and swelling occur reducing stability
Solution Approach 1:
The invention incorporates polyvinyl chloride into the cation-exchange membrane structure in advance, creating a pre-strengthened membrane that can withstand extended electrodialysis operation and high-temperature conditions without peeling or excessive swelling. This beforehand reinforcement ensures membrane stability during high-productivity operation
Solution Approach 2:
The invention modifies the membrane's thermal and mechanical parameters by incorporating polyvinyl chloride, which maintains structural integrity at elevated temperatures and during prolonged use. This parameter modification allows the membrane to maintain stability while supporting extended electrodialysis operation for increased production
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 membrane achieves a gluconic acid leakage ratio of less than 1.0% at 60°C, maintaining strong adhesion and excellent current efficiency by preventing anion passage through gaps, thus ensuring stable electrodialysis performance.
Implementation Method 1
The bipolar membrane is a composite membrane obtained by sticking a cation-exchange membrane and an anion-exchange membrane together, and has a function of dissociating water into protons and hydroxide ions
Implementation Method 2
enhancing adhesiveness by using polyvinyl chloride's high affinity and compatibility with polar solvents, ensuring the membranes remain adhered even under high temperatures
Data Source
AI summary
A bipolar membrane in which a cation-exchange membrane and an anion-exchange membrane are joined to each other, wherein a leakage ratio of gluconic acid at 60°C is not more than 1.0%, and the cation-exchange membrane is supported by a polyolefin reinforcing member and, further, contains a polyvinyl chloride.