Plasma-Activated Water Deionization for Electrode Protection

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Solution Overview

Problem

Existing capacitive deionization devices for water require periodic regeneration of carbon-based electrodes due to oxidation and calcification, which is costly and involves using citric acid to reduce pH, increasing operational expenses.

Innovation Solution

A device with a plasma generator introduces excited ions into the water to lower the pH, reducing electrode degradation without the need for citric acid, using a nitrogen or air plasma to convert water molecules into substances that counteract electrode degradation, and an activated carbon filter to remove excess substances.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If carbon-based electrodes are used for capacitive deionization, then deionization function is achieved, but electrode degradation occurs due to oxidation and calcification

Engineering Contradiction:
Improveelectrode service lifeVSAvoidelectrode degradation
Core Design Contradiction:
ReliabilityVSObject-affected harmful factors

Solution Approach 1:

The plasma generator is positioned upstream of the deionization cell to pre-treat the water by generating excited ions and reactive species before the water contacts the electrodes. This preliminary action modifies the water chemistry to create a protective effect against electrode degradation without requiring chemical additives.

Inventive Principle:
Principle #10Preliminary action

Solution Approach 2:

The plasma-generated excited ions and reactive species act as intermediaries between the water and the electrodes. These intermediaries lower the pH and create a chemical environment that protects the carbon-based electrodes from oxidation and calcification, reducing direct harmful interactions.

Inventive Principle:
Principle #24Intermediary (Mediator)

2Reliability

If citric acid is added to reduce pH and protect electrodes, then electrode degradation is reduced, but additional costs and operational complexity increase

Engineering Contradiction:
Improveelectrode service lifeVSAvoidsystem complexity
Core Design Contradiction:
ReliabilityVSDevice complexity

Solution Approach 1:

The plasma generator creates a self-sustaining chemical environment by continuously generating excited ions and reactive species that lower the pH. The system uses its own plasma generation capability to maintain protective conditions without requiring external chemical additives or complex delivery systems.

Inventive Principle:
Principle #25Self-service

Solution Approach 2:

The mechanical/chemical system of citric acid storage and dosing is replaced with a plasma generation system. The plasma generator uses electrical energy to create reactive species in situ, eliminating the need for chemical storage tanks, dosing pumps, and associated control systems.

Inventive Principle:
Principle #28Mechanics substitution (Replace mechanical system)

3Reliability

If citric acid is added to reduce pH and protect electrodes, then electrode degradation is reduced, but operational expenses increase

Engineering Contradiction:
Improveelectrode service lifeVSAvoidoperational cost
Core Design Contradiction:
ReliabilityVSLoss of energy

Solution Approach 1:

The plasma generator uses inexpensive, short-lived excited ions and reactive species that are continuously generated and consumed. These transient species perform the pH-lowering function without requiring expensive chemical additives like citric acid, reducing operational expenses while maintaining electrode protection.

Inventive Principle:
Principle #27Cheap short-living objects (Disposable)

4Productivity

If plasma generator is placed in side channel, then main water flow is not disrupted, but only small amount of water contacts plasma

Engineering Contradiction:
Improvedeionization throughputVSAvoidwater treated by plasma
Core Design Contradiction:
ProductivityVSQuantity of substance

Solution Approach 1:

The plasma treatment is applied locally in the side channel where a portion of the water flow receives the full plasma effect. This localized treatment creates a chemically modified water stream that then mixes with the main flow, providing electrode protection without requiring the entire water volume to pass through the plasma zone.

Inventive Principle:
Principle #3Local quality

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 method effectively reduces electrode degradation, achieving a similar pH reduction effect to citric acid use without additional chemical costs, thereby extending the lifespan of carbon-based electrodes and simplifying the deionization process.

Implementation Method 1

The plasma generator is set up to provide a substance in the form of a plasma and to introduce it into the water

Methodology Applied
Scientific EffectPlasma: Plasma

Implementation Method 2

ions excited by means of the activation device can be introduced into the water. The excited ions may be capable of reacting with the water present

Methodology Applied
Scientific EffectIon excitation: Ionisation

Implementation Method 3

The water to be deionized is converted into nitrates and/or nitrites and/or protonated water molecules and/or hydrogen peroxide with the nitrogen plasma

Methodology Applied
Scientific EffectChemical reaction: Chemical Bonding

Implementation Method 4

an activated carbon filter to remove excess substances

Methodology Applied
Scientific EffectAdsorption: Adsorption

Data Source

PatentEP4029835B1Device for deionising water
Publication Date: 2023.08.09 ROBERT BOSCH GMBH
  • EP4029835B1 patent drawingFigure 1~2

AI summary

The invention relates to a device for deionizing water, comprising a cell with two electrodes for capacitive deionizing the water and an activation device, wherein excited ions can be introduced into the water by means of the activation device. The invention further relates to an operating method for this device, which comprises the following steps: introducing excited ions into the water by means of an activation device and capacitive deionizing of the water.