Hydrophobic Deep Eutectic Solvent Extraction for PFAS Removal
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Solution Overview
Problem
Existing methods for removing per- and polyfluoroalkyl substances (PFASs) from water suffer from low removal efficiencies, poor selectivity, and high energy requirements, with membrane systems prone to fouling and adsorption systems losing effectiveness over time.
Innovation Solution
A method involving liquid-liquid extraction using a hydrophobic deep eutectic solvent, such as a mixture of trioctylphosphine oxide and lauric acid, to effectively extract PFASs from water by forming strong hydrophobic interactions and hydrogen bonds, allowing for high extraction efficiency and reusability.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If membrane systems are used to remove PFASs from water, then removal efficiency is improved, but the systems are susceptible to fouling and require high energy input
Solution Approach 1:
The patent extracts PFASs from water using liquid-liquid extraction with deep eutectic solvents, separating the contaminant removal function from membrane filtration. This avoids membrane fouling while achieving high removal efficiency through selective partitioning of PFASs into the organic phase.
Solution Approach 2:
The deep eutectic solvent acts as an intermediary substance that facilitates PFAS removal without direct contact between water and the extraction mechanism. The solvent mediates the transfer of PFASs from aqueous to organic phase, eliminating the need for membranes that are prone to fouling.
2Reliability
If adsorption systems are used to remove PFASs from water, then removal efficiency is improved, but the systems lose effectiveness over time
Solution Approach 1:
The patent enables recovery and reuse of the deep eutectic solvent after extraction. The solvent can be regenerated by back-extraction or evaporation, allowing multiple reuse cycles and maintaining consistent removal efficiency over time, unlike adsorption materials that become saturated and require replacement.
Solution Approach 2:
The extraction system maintains continuous effectiveness through solvent regeneration and reuse. The deep eutectic solvent can be repeatedly cycled between extraction and regeneration stages, providing sustained removal capability without the degradation issues that plague adsorption systems over time.
3Productivity
If conventional extraction solvents are used, then extraction efficiency is achieved, but viscosity is too high for practical application
Solution Approach 1:
The patent modifies the physical parameters of extraction solvents by using deep eutectic solvents with specifically tuned viscosity characteristics. These solvents achieve the optimal balance between extraction efficiency and fluidity, with viscosities low enough for practical handling and processing while maintaining high PFAS affinity.
Solution Approach 2:
The deep eutectic solvents are composite systems formed by combining hydrogen bond donors and acceptors in specific ratios. This composite approach creates solvents with tailored properties, achieving both high extraction efficiency for PFASs and appropriate viscosity for practical application, unlike conventional single-component solvents.
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 deep eutectic solvent achieves extraction efficiencies greater than 99% with multiple reuse cycles, maintaining effectiveness across varying pH, temperature, and solvent-to-feed ratios, outperforming traditional methods in efficiency and cost-effectiveness.
Implementation Method 1
the second liquid includes a hydrophobic deep eutectic solvent
Implementation Method 2
forming strong hydrophobic interactions and hydrogen bonds
Implementation Method 3
A method involving liquid-liquid extraction using a hydrophobic deep eutectic solvent
Data Source
AI summary
A method for liquid-liquid extraction includes contacting a first liquid with a second liquid sufficient to extract one or more per- and polyfluoroalkyl substances (PFASs) from the first liquid, wherein the second liquid includes a deep eutectic solvent.