A generic solvothermal defluorination method for carboxylate and sulfonate PFAS
Neal Strijckmans1, Wouter Stuyck1, Floris Hooyberghs1
1Centre for Membrane Separations, Adsorption, Catalysis and Spectroscopy for Sustainable Solutions (cMACS), KU Leuven Leuven 3001 Belgium dirk.devos@kuleuven.be.
Chemical Science
|July 13, 2026
Summary
A new solvothermal method efficiently degrades diverse per- and polyfluoroalkyl substances (PFAS) into inorganic fluoride under mild conditions. This approach utilizes alcohol co-solvents for enhanced defluorination and is effective even on PFAS-contaminated materials.
Area of Science:
- Environmental Chemistry
- Green Chemistry
- Materials Science
Background:
- Per- and polyfluoroalkyl substances (PFAS) are persistent environmental contaminants.
- Existing remediation technologies often require harsh conditions or are incomplete.
Purpose of the Study:
- To develop a milder, more effective method for complete PFAS mineralization.
- To investigate the role of alcohol co-solvents in PFAS degradation.
Main Methods:
- Solvothermal treatment at 220 °C with 8 M KOH and 50 vol% methanol.
- Use of sealed pressure batch reactors for complete fluorine recovery.
- Analysis using multinuclear NMR, FTIR, and chromatography.
Main Results:
- >99% conversion of various PFAS (PFCAs, PFSAs, GenX) to inorganic fluoride.
- Demonstrated effectiveness on PFAS-loaded granular activated carbon (GAC).
- Identified reaction intermediates and pathways facilitated by alcohol co-solvents.
Conclusions:
- The developed solvothermal method offers a promising solution for complete PFAS destruction.
- Alcohol co-solvents enhance degradation efficiency through dual mechanisms.
- The method is applicable to real-world contaminated matrices.
Related Concept Videos
01:18Carboxylic Acids to Acid Chlorides
Carboxylic acids react with SOCl2 or PCl5 to form acid chlorides. Amongst the carboxylic acid derivatives, acid chlorides are the most reactive and synthetically important derivatives. They are useful reagents for Friedel–Crafts acylation of some aromatic compounds.
04:01Factors Affecting Solubility
Compared with pure water, the solubility of an ionic compound is less in aqueous solutions containing a common ion (one also produced by dissolution of the ionic compound). This is an example of a phenomenon known as the common ion effect, which is a consequence of the law of mass action that may be explained using Le Chȃtelier’s principle. Consider the dissolution of silver iodide:
01:08Sample Preparation for Analysis: Advanced Techniques
Accurate analysis of complex samples often requires advanced preparation techniques to achieve reliable and reproducible results. Samples containing inorganic or organic materials can be challenging to dissolve or decompose effectively. Standard sample preparation methods include acid digestion, fusion, dry ashing, and wet digestion.
Acid digestion with strong acids is commonly used to dissolve inorganic materials that are insoluble (do not dissolve) in water. This method can be useful for...
Acid digestion with strong acids is commonly used to dissolve inorganic materials that are insoluble (do not dissolve) in water. This method can be useful for...
01:17Precipitation and Co-precipitation
Precipitation and coprecipitation methods can be used to separate a mixture of ions in a solution. In qualitative inorganic analysis, ions that form sparingly soluble precipitates with the same reagent are separated based on the differences in solubility products. For example, consider the separation of Cu(II) and Fe(II) ions by precipitation as insoluble sulfides. First, copper(II) sulfide is precipitated by the addition of acidic H2S, where the dissociation of H2S is suppressed. Adding H2S...
01:01Acid Halides to Carboxylic Acids: Hydrolysis
Hydrolysis of acid halides is a nucleophilic acyl substitution reaction in which acid halides react with water to give carboxylic acids. The reaction occurs readily and does not require acid or a base catalyst.
As shown below, the mechanism involves a nucleophilic attack by water at the carbonyl carbon to form a tetrahedral intermediate. This is followed by the reformation of the carbon–oxygen π bond along with the departure of a halide ion. A final proton transfer step yields carboxylic acid...
As shown below, the mechanism involves a nucleophilic attack by water at the carbonyl carbon to form a tetrahedral intermediate. This is followed by the reformation of the carbon–oxygen π bond along with the departure of a halide ion. A final proton transfer step yields carboxylic acid...