Capacitive Deionization Electrode Sterilization via In-Situ Chlorine Generation

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Solution Overview

Problem

CDI-type water treatment devices face issues with bacterial growth in the filter electrodes, leading to reduced lifespan, increased pressure drop, and compromised purification performance, which existing methods address by introducing chemical sterilization substances that can cause additional problems.

Innovation Solution

A CDI-type water treatment device with a sterilization unit that generates a sterilization substance from raw water, specifically reducing chlorine ions to chlorine gas, which is used to sterilize the electrodes without the need for additional chemical substances, maintaining TDS rejection and preventing bacterial growth.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If chemical sterilization substances are introduced to sterilize the electrode part, then sterilization effect is improved, but device complexity and potential harm to electrodes increase

Engineering Contradiction:
Improvesterilization effectVSAvoiddevice complexity
Core Design Contradiction:
ReliabilityVSDevice complexity

Solution Approach 1:

The system utilizes the raw water itself as the source of sterilization substance through electrochemical generation at the electrode surface. The electrode part generates chlorine from chloride ions in the raw water during operation, eliminating the need for external chemical sterilization substances and simplifying the device structure while maintaining effective sterilization

Inventive Principle:
Principle #25Self-service

Solution Approach 2:

The electrode part acts as an intermediary that transforms chloride ions in the raw water into chlorine sterilization substance through electrochemical reaction. This mediator approach converts a harmless component of raw water into an effective sterilant without requiring external chemical additions

Inventive Principle:
Principle #24Intermediary (Mediator)

2Reliability

If chemical sterilization substances are continuously supplied to sterilize the electrode part, then bacterial growth is prevented, but TDS rejection performance deteriorates

Engineering Contradiction:
Improvesterilization effectVSAvoidTDS rejection
Core Design Contradiction:
ReliabilityVSManufacturing precision

Solution Approach 1:

The system performs sterilization periodically during specific operational phases rather than continuous chemical supply. The electrode part generates sterilization substance naturally during normal water purification operation and regeneration cycles, achieving periodic sterilization that maintains TDS rejection performance while preventing bacterial growth

Inventive Principle:
Principle #19Periodic action

Solution Approach 2:

The electrode part self-generates the sterilization substance through electrochemical reactions during its normal operational cycles, eliminating the need for external chemical supply systems that would compromise TDS rejection. The system uses its own operational energy to produce the sterilant

Inventive Principle:
Principle #25Self-service

3Reliability

If chemical sterilization substances are used to sterilize the filter, then bacterial growth is inhibited, but electrode lifespan is reduced

Engineering Contradiction:
Improvesterilization effectVSAvoidelectrode lifespan
Core Design Contradiction:
ReliabilityVSDuration of action of stationary object

Solution Approach 1:

The electrode part generates the sterilization substance through its own electrochemical reactions during normal operation, avoiding exposure to external harsh chemical sterilants. This self-generated chlorine from raw water chloride ions effectively sterilizes without causing the degradation associated with external chemical treatments, extending electrode lifespan

Inventive Principle:
Principle #25Self-service

Solution Approach 2:

The system converts the potentially harmful effect of chloride ions (which can form corrosive chlorine) into a beneficial sterilization mechanism. By controlling the electrochemical generation of chlorine at the electrode surface, the system transforms what could be a corrosive threat into an effective sterilant that protects the electrode from bacterial fouling without excessive chemical exposure

Inventive Principle:
Principle #22Blessing in disguise (Convert harm into benefit)

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 effectively sterilizes the electrodes without chemical substances, inhibiting pressure drop increases and maintaining contaminant rejection, thus extending the device's lifespan and ensuring continuous purification performance.

Implementation Method 1

The CDI method refers to a method of removing an ion (a contaminant) using a principle of adsorbing and desorbing ion at a surface of an electrode by an electrical force

Methodology Applied
Scientific EffectAdsorption: Adsorption

Implementation Method 2

adsorbing and desorbing ion at a surface of an electrode by an electrical force

Methodology Applied
Scientific EffectElectrical force: Lorentz Force

Implementation Method 3

it is necessary to desorb the ions adsorbed in the electrode to regenerate the electrode

Methodology Applied
Scientific EffectDesorption: Desorption

Implementation Method 4

The CDI-type water treatment device reduces chlorine ion (Cl-) in raw water to chlorine (Cl 2 ) to generate the sterilization substance

Methodology Applied
Scientific EffectReduction: Reduction

Data Source

PatentEP3088366B1Method for water treatment using a capacitive deionization device
Publication Date: 2021.11.10 COWAY CO LTD
  • EP3088366B1 patent drawingFigure 1
  • EP3088366B1 patent drawingFigure 2
  • EP3088366B1 patent drawingFigure 3

AI summary

A CDI-type water treatment device according to the present invention comprises: a filter unit for purifying raw water in a CDI type through an electrode part formed by alternately stacking electrodes and separators; and a sterilization unit provided on the front of the filter unit to supply the electrode part with a sterilization substance, which has been generated from the raw water in order to sterilize the electrode part. The sterilization unit, in this case, preferably operates after a predetermined time has passed since the electrode part has both stopped purifying raw water and stopped regenerating the electrodes.