Electrical discharge plasma reaction structure with improved process stability and selectivity towards short-chain PFAS degradation
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Solution Overview
Problem
Existing reaction structures face challenges in effectively degrading short-chain PFAS due to foam interference and limited selectivity in plasma treatment, which affects treatment efficiency and compliance with environmental regulations.
Innovation Solution
A reaction structure with integrated gas phase and liquid phase electrode arrays, including a defoamer, generates plasma discharges to degrade PFAS, where the gas phase electrode array reduces foam accumulation and the liquid phase electrode array enhances treatment selectivity through secondary plasma discharges, effectively degrading both short and long-chain PFAS.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If plasma discharge is used to degrade PFAS, then degradation effectiveness is improved, but foam interference increases and process stability deteriorates
Solution Approach 1:
The patent extracts and removes foam from the plasma treatment zone using a separate defoamer device positioned adjacent to the plasma discharge area. This separates the foam management function from the plasma generation function, allowing plasma to effectively degrade PFAS while foam is simultaneously removed, thereby maintaining process stability without reducing degradation effectiveness.
Solution Approach 2:
The defoamer acts as an intermediary device between the plasma discharge and the liquid bulk. It mediates the interaction by capturing and removing foam bubbles that would otherwise interfere with plasma discharge stability, enabling continuous effective plasma treatment while preventing foam-related process disruptions.
2Productivity
If conventional plasma treatment is used, then general PFAS degradation is achieved, but selectivity towards short-chain PFAS is insufficient
Solution Approach 1:
The patent applies local quality by creating a specialized treatment zone at the liquid-gas interface where plasma discharge occurs. This localized plasma generation at the surface provides enhanced selectivity for short-chain PFAS which concentrate at the interface, while the bulk liquid treatment continues simultaneously. The local plasma zone creates concentrated reactive species that preferentially degrade short-chain PFAS.
Solution Approach 2:
The treatment process is segmented into multiple functional zones: a plasma discharge zone at the liquid-gas interface for selective short-chain PFAS degradation, and a bulk liquid treatment zone for general PFAS removal. This segmentation allows different treatment mechanisms to operate simultaneously, providing both selectivity and overall degradation effectiveness.
3Quantity of substance
If foam is present in the reaction structure, then liquid volume is maintained, but plasma discharge stability is reduced
Solution Approach 1:
The defoamer device continuously extracts foam bubbles from the liquid surface and plasma discharge zone. By removing foam while maintaining liquid volume through controlled gas sparging, the system preserves plasma discharge stability without compromising liquid level, effectively separating foam removal from volume maintenance functions.
Solution Approach 2:
The system maintains continuous plasma discharge stability by continuously removing foam as it forms. The defoamer operates concurrently with plasma generation, ensuring that foam does not accumulate to interfere with discharge stability, while liquid volume is maintained through ongoing gas-liquid mass transfer.
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 integrated electrode arrays provide stable plasma treatment by minimizing foam interference and achieving selective degradation of PFAS, ensuring compliance with environmental standards by efficiently reducing both short and long-chain PFAS concentrations.
Implementation Method 1
There is a plasma discharge from the gas phase electrode array integrated with defoamer
Implementation Method 2
The secondary plasma discharge can occur at the tip of the tubes forming part of the liquid phase electrode array with integrated gas bubbler
Implementation Method 3
gas phase electrode array integrated with defoamer
Data Source
AI summary
Disclosed are embodiments of a reaction structure which has a gas phase electrode array integrated with defoamer, a container, a head space gas, bulk liquid, and a liquid phase electrode array with integrated gas bubbler, which emits process gas. There is a plasma discharge from the gas phase electrode array integrated with defoamer. The bulk liquid contains per- and polyfluoroalkyl substances (PFAS) chemicals, including short chain PFAS, which are degraded. In embodiments, a secondary plasma discharge can occur from the liquid phase electrode array with integrated gas bubbler. This secondary plasma discharge can be effective at degrading short-chain PFAS, which has a hard time gaining exposure to the plasma discharge formed from the gas phase electrode array integrated with defoamer. Also disclosed are embodiments of a process of use of the reaction structure to degrade PFAS.