PFAS Destruction Reactor With Membrane Reject Recycling
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Solution Overview
Problem
Existing methods for destroying PFASs are energy-intensive, prone to clogging, or ineffective against shorter chain PFASs, and there is a need for more efficient and effective processes to reduce their presence in the environment.
Innovation Solution
The use of UV irradiation at 222 nm with additives such as sulfite salts, halide salts, and bases, combined with thermal oxidation and electrochemical processes, to enhance PFAS destruction in aqueous solutions, including pretreatment and post-treatment steps to minimize interference from other chemical species.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If supercritical water oxidation (SCWO) is used to destroy PFASs, then destruction efficiency is improved, but energy consumption increases and clogging issues occur
Solution Approach 1:
The patent changes the physical-chemical parameters of the oxidation process by using subcritical water conditions (lower temperature and pressure than supercritical) combined with specific pH adjustments and oxidation agents. This alternative parameter set achieves effective PFAS destruction while avoiding the high energy consumption and clogging problems associated with supercritical conditions.
2Reliability
If hydrothermal alkaline treatment (HALT) is used to destroy PFASs, then destruction efficiency is improved, but equipment complexity increases due to high pressure requirements
Solution Approach 1:
The patent replaces the mechanical high-pressure system of HALT with a chemical approach using oxidation agents and pH control at atmospheric or near-atmospheric pressure. This substitution eliminates the need for complex high-pressure equipment while maintaining effective PFAS destruction through chemical oxidation mechanisms.
3Reliability
If electrochemical destruction is used for long chain PFASs, then destruction efficiency is improved, but effectiveness against shorter chain PFASs deteriorates
Solution Approach 1:
The patent creates a universal oxidation system that effectively destroys PFASs across all chain lengths. By using oxidation agents that can attack the carbon-fluorine bonds in PFAS molecules regardless of chain length, the system achieves broad-spectrum effectiveness unlike electrochemical methods that are limited to longer chain compounds.
4Reliability
If basic aprotic media are used to destroy PFASs, then destruction efficiency is improved, but ease of operation deteriorates due to water transfer requirements
Solution Approach 1:
The patent allows the treatment system to work directly with aqueous waste streams without requiring transfer to aprotic media. The oxidation process is designed to function in water-based environments, eliminating the need for complex phase transfer operations and making the system easier to operate while maintaining destruction efficiency.
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
Achieves greater than 90% to 99% destruction of PFASs efficiently, with the potential for recycling materials and reducing operational costs through optimized reactor designs and pretreatment processes.
Implementation Method 1
irradiating the aqueous solution with light at 222 nm
Implementation Method 2
subjecting the aqueous solution containing PFAS to an increased temperature and pressure for a period of time sufficient for thermal oxidation
Data Source
AI summary
Methods, systems, and devices for PFAS destruction including providing water containing PFAS to a reactor vessel, irradiating the water with UV light under conditions to destroy at least a portion of the PFAS, passing the treated water through a selective membrane to form permeate and membrane reject comprising PFAS, providing the membrane reject back to the reactor vessel, providing additional water containing PFAS to the reactor vessel within the reactor vessel or before being provided to the reactor vessel, and irradiating the membrane reject and the additional water containing PFAS within the reactor vessel with UV light. The steps may be repeated a plurality of times such that PFAS that is not destroyed is recycled through the reactor vessel. Sensitizers may be added and may also be recycled in the membrane reject with the PFAS.