The Segmentation of PFAS That Changes PFAS Treatment & Destruction

Per- and polyfluoroalkyl substances (PFAS) are a family of synthetic chemical compounds that contain multiple fluorine atoms attached to an alkyl chain. The OECD states that "fluorinated substances that contain at least one fully fluorinated methyl or methylene carbon atom (without any H/Cl/Br/I atom attached to it), i.e. with a few noted exceptions, any chemical with at least a perfluorinated methyl group (-CF₃) or a perfluorinated methylene group (-CF₂-) is a PFAS." Under this definition, PFAS is an incredibly large family of synthetic chemicals containing over 10,000 substances.

 

With so many PFAS in use worldwide, it is unsurprising that PFAS contamination has become a global issue impacting human and environmental health. In the United States alone, there are an estimated 57,000+ sites of PFAS contamination, according to a 2022 study from the PFAS Project Lab at Northeastern University. Extensive remediation efforts will need to be conducted to deal with such widespread PFAS contamination, which will cost a significant amount of money. IDTechEx's latest report, "PFAS Treatment 2025-2035: Technologies, Regulations, Players, Applications", estimates that global expenditure on PFAS treatment for municipal drinking water alone will reach US$2.3 billion in 2035.

 

 

Treating PFAS in water and soil is a major task by its magnitude alone; however, another complicating factor is the type of PFAS being treated. The characteristics of a PFAS, such as its mobility and persistence in the environment, depend on the size of the PFAS molecule. This subsequently significantly impacts the choice and efficiency of different PFAS treatment technologies. As such, the broader PFAS family can be segmented into three critical-to-understand categories: long-chain, short-chain, and ultra-short-chain.

 

 

 

Long-chain PFAS are defined by the number of carbon atoms in the main "backbone" or chain of the molecule. Long-chain sulfonic-based PFAS have 6 or more carbons, while long-chain carboxylic acid-based PFAS have 8 or more carbons. Representative examples of long-chain PFAS include PFOA (perfluorooctanoic acid) and PFOS (perfluorooctanoic sulfonic acid), the two most publicized PFAS.

 

Long-chain PFAS were (and still are, to some extent) used extensively in different applications, such as the manufacturing of fluoropolymers like Teflon and in aqueous film-forming foams (AFFF) for firefighting, beginning in the 1940s. For this reason, they are sometimes called "legacy" PFAS.

 

 

More recently, there is growing awareness of the negative health and environmental effects of long-chain PFAS, though most research is primarily centered on PFOA and PFOS. The major issue is their ability to accumulate and persist in the environment for long periods. This has resulted in their steady phase-out in usage through voluntary and regulatory actions. For example, the Stockholm Convention banned PFOS, PFOA, and PFHxS in 2009, 2019, and 2022, respectively; much of the world, including most countries in the European Union, follows the convention. In 2000, 3M voluntarily ceased manufacturing of PFOS and related substances. Many countries also regulate the acceptable level of PFOA/PFOS in drinking water; the USA recently instituted the world's lowest limits for PFOA/PFOS in drinking water at 4 ppt (parts per trillion) each.

 

 

Short-chain PFAS can be defined as sulfonic-based PFAS with 4 to 5 carbons or carboxylic acid-based PFAS with 4 to 7 carbons. Representative examples of short-chain PFAS include PFBA (perfluorobutanoic acid) and PFBS (perfluorobutanesulfonic acid).

 

Short-chain PFAS were introduced as less bioaccumulative, and thus less toxic, alternatives to long-chain PFAS as research on the toxicity of the latter became more available. While short-chain PFAS are slightly less bioaccumulative than long-chain PFAS, they are still highly persistent in the environment. Concerningly, short-chain PFAS are more mobile than their long-chain PFAS counterparts, enabling them to migrate far beyond where they were first introduced to the environment. This is leading to increased research on the health effects of short-chain PFAS.

 

 

While short-chain PFAS are mostly unregulated in their use, they are beginning to be targeted through regulations on PFAS in drinking water. For example, PFBS was included in the US's new limits on PFAS in drinking water; Canada included PFBS, PFBA, and PFHxA in its limits on PFAS in drinking water, which stipulates that the sum of 25 PFAS (including several short-chain PFAS) must not exceed 30 ng/L.

 

 

Ultra-short-chain PFAS refer to PFAS (both sulfonic and carboxylic acid-based) with carbons less than 4. Examples of ultra-short-chain PFAS include PFPrA (perfluoropropionic acid) and TFA (trifluoroacetic acid).

 

While ultra-short-chain PFAS have their own use cases (i.e. TFA is widely used in organic synthesis applications), they are also formed as byproducts of the degradation of other longer PFAS. This is how their levels have significantly increased in the environment despite their usage not increasing at the same rate. Now, research is emerging that ultra-short-chain PFAS may have similar issues as their short and long-chain counterparts with even higher mobility in the environment. For example, one German chemical regulatory agency recommended that TFA be classified as reprotoxic, meaning that it can harm human reproductive function, to the European Chemicals Agency (ECHA). However, unlike long-chain and short-chain PFAS, these compounds have largely gone unregulated in both their usage and acceptable water limits.

 

 

 

Understanding the different categories of PFAS is critical for understanding the future trajectory of PFAS treatment. While numerous options exist for treating and destroying long-chain PFAS, it is not certain that regulatory focus will stay on long-chain PFAS. In the future, it is possible for regulations to emerge that also target short-chain and ultra-short-chain PFAS, as more studies on their impact are conducted and published. This would fundamentally change PFAS treatment and PFAS destruction strategies, because most PFAS treatment technologies do not have the same efficacy for long-chain, short-chain, and ultra-short-chain PFAS. Generally speaking, the shorter the chain, the more difficult it is to remove and destroy the PFAS. Future technology development will need to move with, if not ahead of, regulations for all PFAS to be effectively remediated from the environment.

 

 

For more information on the science and complexities of PFAS treatment, refer to IDTechEx's leading report, "PFAS Treatment 2025-2035: Technologies, Regulations, Players, Applications". IDTechEx appraises each technology, both incumbent and emerging, to analyze its potential in the different application areas needing PFAS treatment. Player landscapes accompany this to establish the activity in each treatment area and technology. A 10-year market forecast on PFAS treatment for municipal drinking water is also provided. IDTechEx's comprehensive discussion and analysis will offer a clear picture of the dynamic PFAS treatment market for those looking to understand this rapidly emerging field in sustainability.

 

 

For more information on this report, please visit www.IDTechEx.com/PFASTreat. Downloadable sample pages are available for this report.

 

For the full portfolio of sustainability market research available from IDTechEx, please see www.IDTechEx.com/Research/Sustainability.

IDTechEx provides trusted independent research on emerging technologies and their markets. Since 1999, we have been helping our clients to understand new technologies, their supply chains, market requirements, opportunities and forecasts. For more information, contact research@IDTechEx.com or visit www.IDTechEx.com.