Fluoropolymers are essential materials in today’s world, found in both industry and consumer products. However, when they reach the end of their lifespan, they contribute to waste streams, both industrial and household. Researchers have explored how incinerating these fluoropolymers affects the release of low-molecular, non-polymeric fluorinated compounds. Their studies indicate that combustion at the typical temperatures and durations used in European incinerators effectively destroys almost all fluoropolymers.
Fluoropolymers are essential materials in today’s world, found in both industrial and consumer products. However, when they reach the end of their lifespan, they contribute to waste streams, both industrial and household. Collaborating with international partners, researchers from the Karlsruhe Institute of Technology (KIT) have examined the extent to which incineration of fluoropolymers releases low-molecular, non-polymeric fluorinated compounds. Experiments conducted at KIT’s BRENDA incineration facility demonstrated that combustion effectively destroys nearly all fluoropolymer materials at temperatures and residence times commonly found in European incinerators. This study has been published in the journal Chemosphere.
Unlike fluoropolymers—also known as “polymeric PFAS,” which are stable and non-bioaccumulative and used in sectors such as healthcare, technology, aerospace, automotive, and chemical manufacturing—”low-molecular PFAS” appear in a broad array of consumer products. Examples include water-repellent treatments found in textiles, food packaging like pizza and burger boxes, and baking paper. The PFAS group includes around 10,000 different substances, with fluoropolymers constituting only a small subset of 38 unique substances.
Some of the low molecular weight PFAS are believed to be harmful to health, linked to organ damage and cancer. These substances can accumulate in groundwater and soil, causing environmental concerns and posing risks to public health, while fluoropolymers, with their high molecular weight, are deemed safe for health and the environment.
Researchers Investigate the Effectiveness of Incineration Processes
Led by Dr. Hans-Joachim Gehrmann at KIT’s Institute for Technical Chemistry (ITC), a research team assessed whether the incineration of fluoropolymers leads to environmental release of low molecular weight PFAS. Collaborating with Gujarat Fluorochemicals, a leading Indian fluoropolymer manufacturer, they conducted tests using the BRENDA pilot-scale incineration facility at KIT. The team burned fluoropolymers and subsequently analyzed PFAS concentrations in scrubber water, ash, and flue gas, aiming to ascertain if typical conditions in municipal and industrial waste incinerators can fully mineralize fluoropolymers.
Typical Fluoropolymer Sample
The researchers conducted experiments at two temperature settings: 860 degrees Celsius (aligning with European household waste incineration standards) and 1,095 degrees Celsius (standard for hazardous waste incineration). Both scenarios allowed the flue gas a minimum residence time of two seconds in the combustion chamber. “We proved that over 99.99 percent fluoropolymer reduction is attainable at 860 degrees Celsius with a residence time of two seconds. This indicates we nearly fully mineralized fluoropolymers under typical municipal waste incineration conditions,” stated Gehrmann. He added that increasing the temperature to 1,095 degrees Celsius did not significantly enhance the reduction rate, indicating that higher temperatures do not substantially affect fluoropolymer mineralization.
For this study, the team selected a representative fluoropolymer sample that encompasses around 80 percent of the commercially used fluoropolymers globally, including polytetrafluoroethylene (PTFE, commonly referred to as Teflon®), polyvinylidene fluoride (PVDF), perfluoro alkoxy alkane (PFA), and fluoroelastomers (FKM).
Samples were collected at various points during the combustion process: after the combustion chamber, downstream from the boiler, and from flue gas in the stack. The researchers also analyzed samples from wastewater and solid residues. They employed analytical techniques like gas chromatography linked with mass spectrometry to accurately identify and quantify PFAS. Gehrmann expressed optimism, saying, “These findings are promising for the successful elimination of fluoropolymers in municipal waste incineration compliant with European regulations.” However, he cautioned, “Other pathways exist through which PFAS can enter the environment, warranting further examination and evaluation.”
