Atmospheric Plasma Sterilization via pH-Adjusted Liquid Contact

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Solution Overview

Problem

Conventional sterilization methods using plasma are limited in effectively sterilizing microorganisms in liquids or on surfaces due to the need for vacuum environments and the use of harmful chemical agents, and they struggle with achieving complete sterilization without residual chemical agents.

Innovation Solution

A method involving the generation of plasma in contact with a liquid whose pH is adjusted to 4.8 or lower, utilizing radicals such as superoxide anion radicals and hydroperoxy radicals to achieve effective sterilization without the need for vacuum environments or harmful chemicals.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If conventional plasma sterilization methods are used, then sterilization capability is improved, but the need for vacuum environments and harmful chemical agents increases

Engineering Contradiction:

Improvesterilization capabilityVSAvoidvacuum environment requirement

Core Design Contradiction:

ReliabilityVSDevice complexity

Solution Approach 1:

The invention changes the pressure parameter from vacuum to atmospheric pressure, enabling plasma sterilization without vacuum equipment. The process uses atmospheric pressure plasma generated by dielectric barrier discharge to achieve effective sterilization of liquids and surfaces while eliminating the need for complex vacuum systems

Inventive Principle:

Principle #35Parameter changes

Solution Approach 2:

The invention extracts and eliminates the requirement for vacuum environments and harmful chemical agents from the sterilization process. By using atmospheric pressure plasma with pH-adjusted liquids, the method removes the disturbing elements (vacuum requirement and toxic chemicals) while maintaining sterilization effectiveness

Inventive Principle:

Principle #2Taking out (Extraction)

2Reliability

If chemical agents are used for sterilization, then sterilization effectiveness is improved, but harmful residues and detoxification requirements increase

Engineering Contradiction:

Improvesterilization effectivenessVSAvoidchemical agent residues

Core Design Contradiction:

ReliabilityVSObject-generated harmful factors

Solution Approach 1:

The invention converts the harmful chemical sterilization approach into a beneficial plasma-based method. By using atmospheric pressure plasma with pH-adjusted liquids, the process achieves sterilization without leaving harmful chemical residues, eliminating the need for detoxification steps while maintaining or improving sterilization effectiveness

Inventive Principle:

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

Solution Approach 2:

The invention replaces chemical sterilization methods with a physical plasma-based method. Atmospheric pressure plasma generated by dielectric barrier discharge substitutes for chemical agents, providing sterilization through reactive oxygen species and ions without introducing harmful chemical residues that require removal

Inventive Principle:

Principle #28Mechanics substitution (Replace mechanical system)

3Reliability

If high-concentration chemical agents are used for complete sterilization, then sterilization completeness is improved, but detoxification difficulty increases

Engineering Contradiction:

Improvecomplete sterilizationVSAvoiddetoxification process

Core Design Contradiction:

ReliabilityVSDevice complexity

Solution Approach 1:

The invention extracts and eliminates the need for detoxification processes by replacing high-concentration chemical agents with atmospheric pressure plasma. The plasma method achieves complete sterilization without leaving residues that require removal, thereby removing the disturbing detoxification step entirely

Inventive Principle:

Principle #2Taking out (Extraction)

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 approach significantly enhances microbiocidal activity, allowing for complete sterilization of microorganisms in liquids and on surfaces while avoiding the use of harmful chemicals and reducing the need for complex equipment setups.

Implementation Method 1

plasma is generated in a vicinity of or in a manner to make contact with a liquid

Methodology Applied

Scientific EffectPlasma: Plasma

Implementation Method 2

utilizing radicals such as superoxide anion radicals and hydroperoxy radicals to achieve effective sterilization

Methodology Applied

Scientific EffectRadical generation: Ionisation

Implementation Method 3

a liquid whose pH is adjusted to 4.8 or lower

Methodology Applied

Scientific EffectpH adjustment:

Implementation Method 4

radicals generated by the plasma are made contact with the liquid

Methodology Applied

Scientific EffectRadical reaction: Oxidation

Data Source

PatentUS8871146B2Sterilization method and apparatus

Publication Date: 2014.10.28 KITANO CO LTD

AI summary

An object of the present invention is to efficiently sterilize microorganisms present in or on a surface of a liquid. Plasma is generated in a vicinity of or in a manner to make contact with a liquid whose pH value is adjusted to become 4.8 or lower, more preferably 4.5 or lower. The plasma is generated in an atmospheric gas containing nitrogen, e.g., in the air. Superoxide anion radicals (O2−.) that are generated by the plasma react with protons (H+) in the liquid to form hydroperoxy radicals (HOO.). Further, nitrogen and oxygen included in the air are combined together by the action of plasma to form nitrogen oxide such as nitric oxide (NO.). The nitric oxide (NO.) combines with the hydroperoxy radicals (HOO.) to become peroxynitrite (ONOOH(ONOO−)) having a high microbiocidal activity.