Environmentally friendly technology removes poisonous Pfas out of the water

In cooperation with international partners, researchers at Rice University have developed the first environmentally friendly technology to quickly capture and destroy toxic “Forever Chemicals” (PFAS) in the water. The results were recently published in Advanced materialsrepresent an important step towards coping with one of the most stubborn environmental threats in the world.

The study was led by Youngkun Chung, a postdoctoral under the direction of Michael S. Wong, professor at the George R. Brown School of Engineering and Computing in Rice, and in collaboration with Seoktae Kang, Professor at the Korea Advanced of Science and Technology (Kaist), and Keon-Ham Kim, Professor at Pukyung Nationality in South Korea, carried out.

PFAs, short for per- and polyfluoralkyl substances, are synthetic chemicals that were first produced in the 1940s and used in products such as teflon pans, waterproof clothing and food packaging. Her ability to resist heat, fat and water made it valuable for industry and consumers. Due to their resistance, they are not so easily decomposed, which brings them the nickname “chemicals for eternity”.

Nowadays, PfAs appear in water, soil and air all over the world. Studies link with liver damage, reproduction disorders, disorders of the immune system and certain types of cancer. Efforts to clean Pfas were difficult because the chemicals are difficult to remove and destroy them after their release.

Restrictions on current technology

Conventional PFAS cleaning methods are typically based on adsorption, in which molecules adhering to materials such as activated carbon or ion exchange resins. Although these methods are widespread, they have considerable disadvantages: low efficiency, slow performance, limited capacity and the development of additional waste that must be disposed of.

“Current methods for PFAS removal are too slow, inefficient and create secondary waste,” said Wong, professor of molecular nanotechnology at Tina and Sunit Patel and professor of chemical and biomolecular technology, chemistry as well as construction and environmental engineering. “Our new approach offers a sustainable and highly effective alternative.”

A material with real promises

The innovation of the team led by Rice focuses on a layered double hydroxide material (LDH) made of copper and aluminum, which was first discovered by Kim as a doctoral student on the Kaist in 2021. When experimenting with these materials discovered that a wording with nitrate can adsorb Pfas with record -breaking efficiency.

“To my astonishment, this LDH connection Pfas has captured more than 1,000 times better than other materials,” said Chung, the main author of the study and now Fellow at Water (Water Technologies, Entrepreneurship and Research) Institute and Sustainability Institute of Rice. “It also worked incredibly quickly and removed large amounts of PFAs within minutes, about 100 times faster than commercially available carbon filters.”

The effectiveness of the material is based on its unique inner structure. His organized copper-aluminum layers create an ideal environment for the quick and strong binding of PFAS molecules.

In order to test the practicality of the technology, the team evaluated the LDH material in river water, tap water and waste water. In all cases, it proved to be extremely effective and worked well in both static and continuous flow systems. The results indicate great potential for large -scale applications in municipal water treatment and industrial cleaning.

Close the circle: capture and destroy

The removal of Pfas from water is only part of the challenge. It is just as important to destroy them safely. In cooperation with the Rice Professors Pedro Alvarez and James Tour, Chung developed a method for thermal decomposition of the PFAs captured on the LDH material. By heating the saturated material with calcium carbonate, the team removed more than half of the trapped PFAs without releasing toxic by -products. Remarkably, the process also regenerated the LDH, so that it could be reused several times.

Preliminary studies showed that the material can go through at least six complete cycles of recording, destruction and renewal, which makes it the first known environmentally friendly, sustainable system for PFAS removal.

“We are enthusiastic about the potential of this unique LDH-based technology to change the way PFAS-contaminated water sources are treated in the near future,” said Wong. “It is the result of extraordinary international cooperation and creativity of young researchers.”