Electrodeionization Chamber Segmentation for Water Purity
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Solution Overview
Problem
In deionized water production, the presence of weak-acid anion components like carbonic acid and silica in the treated water reduces the purity due to their ability to pass through ion exchange membranes, especially when the concentration chamber is filled with an anion exchanger, leading to contamination of the treated water.
Innovation Solution
The electrodeionization apparatus is designed with a deionization chamber partitioned into two small chambers, where the anion exchanger is placed first, capturing anion components before they reach the treated water, ensuring that carbonic acid and silica do not diffuse into the treated water by being ionized and captured in the downstream anion exchange layer.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Object-affected harmful factors
If the concentration chamber is filled with an anion exchanger to prevent scale formation, then scale generation is suppressed, but weak-acid anion components (carbonic acid and silica) pass through the ion exchange membrane and diffuse into the treated water, reducing purity
Solution Approach 1:
The deionization chamber is divided into a first deionization chamber and a second deionization chamber separated by a cation exchange membrane. The first chamber contains an anion exchanger for capturing anion components, while the second chamber processes water further. This segmentation allows the system to prevent scale formation in the concentration chamber while removing weak-acid anion components that diffuse into the treated water, thus resolving the contradiction between scale prevention and water purity.
2Manufacturing precision
If the deionization chamber is configured with ion exchangers to capture anion and cation components, then deionization performance is improved, but hardness components precipitate to generate scales on the anion exchange membrane surface
Solution Approach 1:
The invention extracts the function of preventing scale formation from the concentration chamber by introducing a specific configuration in the deionization chamber. The first deionization chamber with an anion exchanger captures anion components including those that would otherwise precipitate as scales. This separates the scale-prevention function from the concentration chamber, allowing it to operate without generating scales while maintaining deionization performance.
Solution Approach 2:
The cation exchange membrane acts as an intermediary between the first and second deionization chambers. It selectively allows cations to pass through while blocking anions, thereby preventing hardness components from reaching the concentration chamber where they would precipitate as scales. This intermediary structure enables the system to maintain high deionization performance without generating harmful scale deposits.
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
This configuration effectively prevents the diffusion of carbonic acid and silica into the treated water, maintaining high purity and preventing scale formation, thus enhancing the quality of deionized water production.
Implementation Method 1
the anion exchanger is placed first, capturing anion components before they reach the treated water, ensuring that carbonic acid and silica do not diffuse into the treated water by being ionized and captured in the downstream anion exchange layer
Implementation Method 2
The liberated ion components move to the ion exchange membrane (anion exchange membrane or cation exchange membrane) through the ion exchanger by electrophoresis, undergo electrodialysis in the ion exchange membrane and move into the concentration chamber
Implementation Method 3
The liberated ion components move to the ion exchange membrane (anion exchange membrane or cation exchange membrane) through the ion exchanger by electrophoresis, undergo electrodialysis in the ion exchange membrane and move into the concentration chamber
Implementation Method 4
water-splitting reaction occurs at the interface between the anion exchanger and the cation exchanger in the deionization chamber, thereby generating hydrogen ions and hydroxide ions (2H2O→H++OH)
Data Source
AI summary
An electrodeionization apparatus for producing deionized water comprises a deionization treatment unit including deionization chamber D and a pair of concentration chambers C1 and C2 placed adjacent to deionization chamber D on opposite sides thereof and those concentration chambers are filled with anion exchangers. The deionization chamber D is partitioned by an ion exchange membrane into first small deionization chamber D-1 adjacent to concentration chamber C1 and second small deionization chamber D-2 adjacent to concentration chamber C2. First small deionization chamber D-1 is filled with an anion exchanger. Second small deionization chamber D-2 is filled with an anion exchanger and a cation exchanger in a sequence such that the ion exchanger, through which water that is to be treated finally passes, is the anion exchanger.