EDI Resin Layer Structure for Single-Stage Boron Removal
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Solution Overview
Problem
Existing electrodeionization (EDI) devices struggle to achieve sufficient removal of boron, a weak acid component, especially when reducing its concentration from about 10 μg/L to the ng/L level, often requiring multiple stages to achieve adequate purification.
Innovation Solution
The EDI device incorporates a deionization chamber with a large particle size layer and a mixed particle size layer of ion exchange resins, along with a concentration chamber containing cation exchange resin, and operates with controlled hardness component levels to enhance boron removal efficiency.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Manufacturing precision
If ion exchange resin with small particle size is used in the deionization chamber, then boron removal performance is improved, but electric resistance increases and deionization efficiency decreases
Solution Approach 1:
The patent applies local quality by using different particle sizes of ion exchange resin in different regions of the deionization chamber. Specifically, small particle size resin (0.1-0.4mm) is used in the middle region where high boron removal performance is needed, while large particle size resin (>0.4mm) is used in the upper and lower regions where lower electric resistance is more important. This spatial differentiation resolves the contradiction between removal performance and energy loss.
Solution Approach 2:
The deionization chamber is segmented into three regions (upper, middle, lower) with different ion exchange resin configurations. The middle region contains small particle size resin for high boron removal, while the upper and lower regions contain large particle size resin for low electric resistance. This segmentation allows each region to optimize for its specific function, resolving the overall contradiction.
2Ease of manufacture
If ion exchange resin with uniform particle size is used, then packing ratio control is simplified, but electric resistance increases
Solution Approach 1:
The patent uses a composite structure of ion exchange resins with different particle sizes arranged in specific regions. The combination of small particle size resin (0.1-0.4mm) in the middle region and large particle size resin (>0.4mm) in the upper and lower regions creates a composite filling structure that achieves both low electric resistance and high boron removal performance, overcoming the limitations of uniform particle size resin.
3Device complexity
If single-stage EDI device is used, then device complexity is reduced, but boron removal performance is insufficient for very low concentration requirements
Solution Approach 1:
The patent enhances the deionization chamber's performance by implementing local quality differentiation through three distinct regions with different ion exchange resin configurations. The middle region uses small particle size resin (0.1-0.4mm) for superior boron removal, while the upper and lower regions use large particle size resin (>0.4mm) for optimized flow and reduced resistance. This spatial optimization enables a single-stage device to achieve boron concentration reduction to ng/L level, eliminating the need for multi-stage configurations.
Solution Approach 2:
The patent changes the particle size parameter of ion exchange resin in different spatial locations within the deionization chamber. By using small particle size (0.1-0.4mm) in the middle region and large particle size (>0.4mm) in the upper and lower regions, the system achieves enhanced boron removal performance while maintaining low electric resistance, allowing a single-stage device to meet very low concentration requirements.
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 significantly improves boron removal performance, enabling the production of deionized water with reduced boron concentration to extremely low levels using a single-stage EDI device.
Implementation Method 1
a deionization chamber arranged between an anode and a cathode, filled with an ion exchange resin... boron is removed from the water to be treated
Implementation Method 2
The EDI device is a device for generating deionized water from water to be treated by combining electrophoresis and electrodialysis
Implementation Method 3
The EDI device is a device for generating deionized water from water to be treated by combining electrophoresis and electrodialysis
Data Source
AI summary
An electrodeionization device includes a deionization chamber partitioned by a pair of ion exchange membranes; and a concentration chamber disposed adjacent to the deionization chamber via the ion exchange membrane which is disposed on a side facing a cathode. When representing a particle size of 0.1 mm or more and 0.4 mm or less by small particle size; and a particle side exceeding 0.4 mm by large particle size, a large particle size layer consisting of an ion exchange resin of large particle size, and a mixed particle size layer in which ion exchange resins of large particle size and small particle size are mixed are arranged in the concentration chamber along a flow direction of water to be treated. At least a part of the ion exchange resin filled in the concentration chamber is a cation exchange resin.