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PNNL scientists work to detect and clean up 'forever chemicals'

Manmade chemicals used in nonstick cookware, waterproof clothing, firefighting foam and stain-resistant carpet may be great at repelling water and oils, but these hazardous "forever chemicals" do not break down easily, creating a vexing environmental challenge. Researchers at the Department of Energy's (DOE) Pacific Northwest National Laboratory (PNNL) are providing science and technology to help locate and clean up this group of persistent fluorinated chemicals known as PFAS (perfluoroalkyl and polyfluoroalkyl substances).

For more than half a century, about 4,700 PFAS were used in numerous everyday products. Over time, these chemicals accumulate in the air, water and soil. They also can collect and remain in the human body, potentially leading to adverse health effects, including elevated cholesterol, weakened immunity and cancer. More than 1,500 locations in 49 states, including military bases, are known to have PFAS contamination.

PNNL scientists are developing two technologies to help protect communities and ecosystems from PFAS. One is a sensitive, portable sensor to detect PFAS in the field. The other is an innovative technology to capture the compounds, which could aid cleanup efforts aimed at protecting groundwater.

Today's detection technology requires water samples to be sent to laboratories where sensitive analytic equipment is used to detect and measure ultra-low levels of PFAS consistent with federal and state health limits. The time and cost associated with laboratory measurements only increase the challenge of identifying contaminated locations.

Contrast that with PNNL's lab-on-a-chip sensor, a patent-pending device smaller than a credit card that will be able to accurately detect extremely low levels of PFAS in real time, in the field. Developed with the New Jersey Institute of Technology, the sensor looks like a microscope slide. When water flows through the path etched on its surface, it encounters porous material specially designed to capture PFAS molecules.

At the same time, an electric current is sent through the sensor, immediately providing information about the amount of PFAS captured. Researchers have already shown that the sensor can detect one particular kind of PFAS in a sample at levels as low as 0.5 parts per trillion — 100 times lower than federal health advisory limits.

In addition to being quick and portable, the technology can easily be regenerated and reused. Researchers are working to expand the capability to detect other kinds of PFAS and are seeking partners to license the technology and engineer market-ready devices.

PNNL scientists seeking a cleanup solution are taking a similar approach, designing porous materials that can selectively remove PFAS from water. They customized nanomaterials called metal organic frameworks with a mesh-like structure that acts like a net to capture PFAS compounds while letting other molecules through.

Laboratory tests compared PNNL-developed materials with existing activated carbon filters like those in home and commercial water filters. Using sensitive analytical equipment, scientists measured how the concentration of PFAS in a vial mixed with the materials changed over time. One of their specially tailored materials completely absorbed the compound within seconds, while the activated carbon had little to no effect.

Given these early results, researchers hope to further develop water-stable, inexpensive and scalable materials that can be deployed in the field to filter out contaminants.

In addition, PNNL is applying its chemistry and materials expertise to explore how to destroy the "forever chemical" once it is isolated — looking for alternatives to incineration or landfills.

Read more: https://www.pnnl.gov/news-media/pnnl-scientists-target-dangerous-forever...

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