Froth Flotation Apparatus for PFAS Separation from Water
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Current technologies for removing perfluoroalkyl substances (PFAS) from contaminated groundwater, such as air stripping, pump and treat methods, and in-situ chemical treatments, are ineffective due to the persistence and recalcitrance of PFAS compounds, leading to high costs, large treatment volumes, and environmental risks.
Innovation Solution
A method and apparatus utilizing froth flotation to concentrate PFAS through a gas introduction process in a chamber, creating a froth layer that is then treated with absorptive devices, such as activated carbon or ion exchange resins, to separate and remove PFAS from water.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If air stripping is used to remove volatile organic compounds from groundwater, then VOC removal is achieved, but PFAS contamination remains persistent and ineffective treatment is provided
Solution Approach 1:
The invention changes the physical parameter being exploited for separation from volatility (Henry's law constant) to surface activity (amphiphilic nature). By using froth flotation instead of air stripping, the process targets PFAS's tendency to concentrate at air-water interfaces and adhere to bubbles, rather than relying on volatilization. This parameter change enables effective PFAS removal while maintaining operational efficiency.
2Reliability
If pump and treat methods are used to treat PFAS contaminated groundwater, then water is treated, but treatment costs are high due to large volumes and extended operation periods
Solution Approach 1:
The invention extracts PFAS from the bulk groundwater by introducing air bubbles that attach to PFAS molecules at the air-water interface. The froth layer containing concentrated PFAS is then removed from the surface, effectively extracting the contaminant from the large volume of groundwater without requiring prolonged pumping and treatment of the entire water volume.
Solution Approach 2:
The invention utilizes the phase transition and interfacial phenomena between gas (air bubbles), liquid (groundwater), and the amphiphilic PFAS compounds. PFAS molecules migrate to the gas-liquid interface and are transferred to the froth phase, which can then be separated and removed. This phase-based separation mechanism achieves rapid concentration and removal of PFAS.
3Reliability
If conventional treatment agents such as activated carbon or ion exchange resin are used, then PFAS absorption is achieved, but the agents are sensitive to fouling and require disposal after reaching maximum capacity
Solution Approach 1:
The invention uses pneumatic principles by introducing air bubbles into the groundwater to create froth flotation. Air serves as the separating agent that attaches to PFAS molecules through interfacial phenomena, forming removable froth. This pneumatic approach replaces chemical adsorbents, eliminating fouling issues and disposal requirements while maintaining effective PFAS removal.
4Reliability
If in-situ chemical treatment is applied to degrade PFAS compounds, then chemical degradation is attempted, but PFAS recalcitrance limits success and hazardous chemicals are required
Solution Approach 1:
The invention replaces chemical degradation mechanisms with a physical separation mechanism. Instead of using hazardous chemicals to attempt degradation of recalcitrant PFAS compounds, the process uses mechanical froth flotation where air bubbles physically attach to and carry PFAS molecules to the surface for removal. This mechanical/physical approach avoids the need for hazardous chemicals while effectively removing PFAS.
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 effectively concentrates PFAS, reducing treatment volumes and costs, and achieves removal of priority PFAS compounds to below drinking water criteria without the need for hazardous chemicals, providing a passive and efficient remediation solution.
Implementation Method 1
introducing a flow of gas into the chamber, wherein said introduced gas induces the water in the chamber to flow, and produce a froth layer which is formed at, and which rises above, an interface with the said flow of water and of introduced gas in the chamber
Implementation Method 2
produce a froth layer which is formed at, and which rises above, an interface with the said flow of water and of introduced gas
Implementation Method 3
passing a flow of the water from the chamber through an absorptive treatment device which is arranged to remove therefrom a further amount of the substance
Data Source
AI summary
A method and apparatus is disclosed for separating an amount of an amphiphilic contaminant substance such as PFAS from water. The method comprising the steps of admitting the water which contains the substance into a flotation cell chamber, and then introducing a flow of gas thereinto. The gas is introduced by several different apparatus options for efficient aeration of the chamber, depending on the water being treated. The introduced gas produces a froth layer which is formed at, and which rises above, an interface with the contents of the chamber. The froth layer includes an amount of water and also a concentrated amount of the contaminant substance when compared with its initial concentration. The process then involves collapsing and removing the froth layer, with several options for removing the PFAS from that liquid by re-flotation to reconcentrate the PFAS, or absorption onto a solid substrate material. The treated water an also pass out of the chamber through an absorptive treatment device to remove an amount of the substance not already recovered in the foamate.