Chemists discover a new technique to get rid of PFAS


Steven Depolo

Steven Depolo | Haiku Deck

Aissata Sow

The phrase “plastic is everywhere” is now truer than ever. Plastic is a pollutant that has gained more attention over the past decade. While most people associate plastic pollution with plastic in the oceans, there is a more insidious form of plastic pollution.

Polyfluoroalkyl substances — PFAS — are chemical compounds commonly used in packaging material and pesticides. The chemical composition of PFAS consists of hydrophilic heads and hydrophobic tails with carbon fluoride bonding. The stability of the molecule and its structure prevents it from degrading in the natural environment.

The majority of PFAS are used in non-stick coatings, stain and water-resistant products, protective coatings, architectural resins and firefighter foams.

In the late 1990’s scientists first discovered the presence of PFAS in human blood through the testing of exposed workers. From the 2000s onwards, testing revealed that the range of PFAS contamination in water sources, animals and human blood increased. A study found that 17 out of every 22 people tested had traces of PFAS in their blood.

PFAS enter the biosphere through the manufacturing, usage and disposal of products with the chemicals. During the manufacturing process, PFAS enter the atmosphere, follow the water cycle and end up in the groundwater system. When people use products with PFAS, such as carpets, water bottles or food wrappers, they unknowingly consume them.

The disposal method for PFAS is straightforward. Waste with trace amounts of PFAS are dumped into landfills or rivers that enter public water sources.

The most worrying characteristic about the widespread contamination of PFAS in humans is the long-term health effects. Current research shows PFAS lead to decreased vaccine response in children, increased cholesterol levels, changes in liver enzymes, decrease in birth weight, increased risk for certain types of cancers and high blood pressure.

On a hopeful note, there have been several breakthroughs on breaking down PFAS before more enter the environment. One potential method is by chemically cutting the molecule and exposing it to different solvents, creating byproducts of fluoride and carbon byproducts. This method quickly degrades PFAS without creating any new ones.

Another way to remove PFAS is through incineration. It takes up to 400 degrees Celsius to break down PFA bonds. This method is unpopular because of the amount of air contaminants released during the process.

As of now, the only practical way to remove PFAS in drinking water is through filtration. A combined process utilizing reverse osmosis, ion exchange resin and activated carbon are being used to filter PFAS.

The issue with this process is that it leaves behind a concentrated byproduct of PFAS that cannot be disposed without serious risk of recontamination. Additionally, filters are not fully effective since smaller PFAS can still pass through the osmosis membrane.

Currently the best way agreed by most scientists on breaking down PFAS is simple and inexpensive.

A team of researchers used low heat, a solvent and lye, a soap ingredient, to break down PFAS. The use of lye is ingenious because soap is very good at breaking down lipids. PFAS have a similar structure to lipids, in that they both have hydrophilic heads and hydrophobic tails. The only downside to this approach is it only works on two specific PFAS.

For the general public, until scientists come up with a foolproof solution, the best way forward is to use water filters with the capacity to filter PFAS and reduce the amount of plastic products consumed.