How PFAS are detected, treated, and removed — and where the science is heading
PFAS are among the most persistent chemicals ever created. But science and engineering are rapidly advancing to detect, remove, and ultimately destroy PFAS in water, soil, and consumer products.
How PFAS Are Detected
The gold-standard technique for PFAS testing is: Liquid Chromatography – Tandem Mass Spectrometry (LC-MS/MS)
LC-MS/MS is a highly sensitive laboratory technique used to detect and measure very small amounts of chemicals—often down to parts per trillion.It works in two main steps:
Liquid Chromatography (LC)
The sample is passed through a column to separate PFAS from other substances in the water.
Tandem Mass Spectrometry (MS/MS)
The separated PFAS molecules are ionized, then measured by two mass spectrometers in sequence, allowing scientists to identify and precisely quantify each PFAS compound.
Because PFAS occur in extremely low concentrations and include many chemically similar compounds, LC-MS/MS is considered the gold standard for PFAS testing due to its accuracy, sensitivity, and ability to distinguish individual PFAS chemicals.
Technologies to Remove PFAS From Drinking Water in Practice
Conventional drinking water treatment technologies (coagulation, flocculation, clarification, filtration, and disinfection) have not been found to be effective in removing PFAS. Technologies have been found to remove longer-chain PFAS, such as PFOA and PFOS, from drinking water including activated carbon adsorption, ion exchange resins, and high-pressure membranes. These technologies can be used in drinking water treatment facilities, in point-of-entry systems to treat all the potable water that enters a home or other building, or at the point-of-use of potable water, such as in a kitchen sink. Effective technologies generally fall into three categories:
Granular Activated Carbon (GAC)
Pros
Best for long-chain PFAS (PFOA, PFOS)
Widely used in water treatment plants
Relatively cost-effective
Cons
Short-chain PFAS breakthrough faster
Carbon must be replaced or regenerated
Competes with other organic contaminants
How it works: PFAS molecules “stick” to the surface of the carbon.
Ion Exchange Resins (IX)
Pros
Highly effective for both long- and short-chain PFAS
Fast and efficient
Often used with GAC in hybrid systems
Cons
Resins are expensive
Regeneration produces concentrated brines
Requires careful waste handling
Reverse Osmosis (RO)
Pros
Most effective PFAS removal technology for households
Removes nearly all PFAS compounds
Cons
Produces a waste concentrate
High energy cost for large systems
Requires pre-treatment to avoid membrane fouling
RO is commonly used in under-sink household filtration systems.
Emerging PFAS removing technologies
| Plasma Treatment | Electrochemical Oxidation |
|---|---|
| High-voltage plasma breaks C–F bonds | Using electrical current and special electrodes to degrade PFAS |
| •Works well for concentrated PFAS waste •Energy-intensive •Not yet used at large municipal scale | •Promising laboratory results •Issues with electrode durability •Potential byproduct formation |
A Summary of PFAS Removing Technologies
| Technology Category | Technology | Challenges | Research Needs |
| Field Implemented | Granular Activated Carbon (GAC) | Competitive adsorption with other contaminants including unidentified PFAS; pretreatment often required; faster breakthrough for short-chain PFAS; less economical at high influent concentrations; spent GAC requires regeneration or incineration and may release PFAS. | More comprehensive performance data; adsorption capacity for short-chain PFAS; understanding competition with other contaminants and aqueous species. |
| Ion Exchange (IX) | Competitive adsorption with ions including unidentified PFAS; pretreatment required; short-chain PFAS breakthrough faster; higher media cost; removal efficiencies vary by PFAS; regeneration produces concentrated brine needing treatment; incineration costly and may release PFAS. | Similar needs as GAC; improved cost-benefit analysis for single-use, regenerable, and hybrid IX systems. | |
| Reverse Osmosis (RO) | Membrane fouling; pretreatment required; multi-stage systems needed; membrane cleaning/replacement essential; produces high-volume concentrate requiring disposal; performance affected by temperature; product water may require post-treatment to prevent corrosion; higher cost than GAC/IX. | Further development of membrane technologies; evaluation of removal across a wide range of PFAS and water qualities; cost-effective disposal/treatment options for concentrate streams. | |
| Nanofiltration (NF) | Lower rejection performance than RO; similar fouling and pretreatment challenges as RO. | Assess whether NF advantages can be realized alone or with other systems; similar research needs as RO. | |
| Novel Technologies | Novel Adsorbents (e.g., biochar) | Material performance varies widely; some have limited PFAS adsorption capacity. | Develop more effective and lower-cost adsorbents for PFAS removal. |
| Advanced Oxidation Processes (AOPs) | PFAS are highly resistant to oxidation; may generate unknown or harmful byproducts; limited effectiveness. | Develop oxidation pathways capable of breaking strong C–F bonds; evaluate byproduct formation and toxicity. | |
| Plasma-based Treatment | High energy consumption; scalability challenges; equipment cost. | Increase energy efficiency; optimize reaction conditions and engineering for scale-up. | |
| Electrochemical Oxidation | Electrode stability issues; potential formation of fluorinated byproducts; variable efficiency. | Develop more durable electrode materials; characterize degradation mechanisms and byproducts. | |
| Photocatalysis | Low PFAS reactivity; requires intense light sources; low overall efficiency. | Develop photocatalysts capable of effectively degrading PFAS. | |
| Thermal Treatment | Very high energy demand; incomplete mineralization under some conditions; potential release of intermediates. | Determine specific temperature and residence time needed for complete PFAS mineralization; establish best operational conditions. | |
| Biological Treatment | PFAS are highly resistant to biodegradation; current microbial effectiveness low. | Identify microorganisms or enzymes capable of PFAS transformation or degradation. |
Future Solutions: Where the Science Is Heading
Scientists and engineers are working toward:
✔Cheaper, faster PFAS detection
✔Filters tailored to specific PFAS compounds
✔Technologies that destroy PFAS completely
✔Greener alternatives to PFAS in manufacturing
✔Large-scale remediation of contaminated groundwater
✔Early-warning systems for PFAS releases