They’re used to make items fireproof and waterproof, pans nonstick and popcorn microwaveable in a bag.
They’re handy, even necessary, but the so-called “forever chemicals” now regularly go from products and packaging to the environment and water sources where they linger. They accumulate in people and animals and are linked to multiple health problems.
But scientists at the Johns Hopkins University Applied Physics Laboratory in Laurel say they have made progress in developing better ways to remove and destroy these PFAS, short for perfluoroalkyl and polyfluoroalkyl substances, from municipal and household water systems.
“It’s definitely a complex problem,” said Leslie Hamilton, a materials science engineer who leads the lab’s PFAS remediation team. “But we see water as a critical resource, so it’s a problem for APL to solve.”
It’s not a job for a Brita filter. APL has dedicated 10 scientists for the past couple of years to the effort and has joined other institutions in the hunt for ways to remove more of the chemicals than current methods, and do it more cheaply and in a more environmentally friendly manner.
Forever chemicals have come under increasing scrutiny as their effects become more widely known. The U.S. Environmental Protection Agency plans to strictly limit some types in drinking water. Some states are proposing banning them in food packaging or other products. Other states and cities have begun suing over their contaminated water systems citing connections to cancer and developmental and reproductive health issues.
Maryland sued several manufacturers in May over water contaminations from firefighting foam and consumer products containing PFAS, alleging the companies knew of the dangers.
Baltimore filed a similar suit in November against more than 20 manufacturers of fire suppressant foam containing PFAS. The suit in U.S. District Court in Maryland also accuses them of knowingly allowing hazardous chemicals to contaminate Baltimore’s waterways and water system.
“While Defendants reaped massive profits from the production and sale of PFAS-based AFFF [fire suppressant] products, they saddled Baltimore and its residents with the burden of cleaning up the mess the ordinary and intended use of those products inevitably caused,” the lawsuit said.
Manufacturers including 3M deny acting irresponsibly.
In the meantime, scientists around the country have begun working on solutions. APL scientists believe they have made progress in filtering the chemicals, both so-called long-chain and short-chain ones. The short-chain ones are built to last in water.
“The short-chain PFAS have really been the challenge to capture large-scale in wastewater systems,” said Danielle Nachman, a geochemist and leader of the lab’s PFAS destruction work.
“Our filter gets like 90% of them, and the byproducts created when they’re destroyed are landfillable so they don’t go back into the environment.”
To capture the PFAS, the scientists have adapted an inexpensive off-the-shelf membrane that allows water to pass but captures the destructive chemicals with “whiskers,” or fibers of a synthetic element engineered at APL added to the surface.
The new membrane can be made into a quarter-size filter for a home faucet or a sheet to cover a large municipal water system. The small size worked well in testing, and the group is preparing to scale it up and test thousands of gallons at a time.
This is different from current systems that use activated carbon to absorb heavy metals and the long-chain PFAS, meaning the short chain PFAS still slip through, Nachman said.
Another aspect of APL’s work, which is less far along, is to break down the PFAS into minerals that are safe to throw in the trash. This is a huge undertaking considering the chemical bonding properties that make PFAS good at firefighting also make them nearly impossible to destroy, she said.
The current method is incineration that requires high temperatures and a lot of energy. It can also send harmful elements back into the environment.
The APL scientists are testing a method that uses environmentally friendly materials to create an advanced oxidation process. It involves hydrogen peroxide and ultraviolet light to break the chemicals’ molecular bonds.
“Before we employ this in the field, we need to precisely understand what is happening, the reaction mechanism,” Nachman said. “We’re working on that.”
Another step for the group is creating new chemicals that do the same job as the PFAS but aren’t bad for the planet and living beings.
On that front, APL has been tapped by the Strategic Environmental Research and Development Program, a U.S. Department of Defense initiative, to make military-grade fire retardant foam.
Rather than make a whole new product, scientists say it’ll be faster to look for a safe non-PFAS additive. That is underway.
And once testing proves the safety, efficacy and eco-friendliness of their capture-and-destroy processes and any other new elements they create, Hamilton said, they could license them to commercial manufacturers.
She said they aren’t quite ready to pop the microwave popcorn in celebration, but they expect that could be coming in the next year or two.