KAIST Develops Rapid Removal Technology for Hard-to-Decompose 'Forever Chemicals' (PFAS)

'Per- and polyfluoroalkyl substances (PFAS)' are often referred to as 'forever chemicals' because they hardly decompose in nature. While these substances are essential for products such as non-stick pan coatings and semiconductor manufacturing processes, concerns have been raised that, after use, they become a source of contamination in tap water and rivers, posing a long-term threat to human health. Although PFAS are necessary, their disposal after use has long been a major challenge.

Recently, technology developed to address this issue has attracted significant attention. KAIST and an international research team have succeeded in developing a method that removes PFAS up to 1,000 times faster than existing technologies.

(From left) Professor Kim Gunhan of Pukyong National University, Dr. Jung Myungkyun of Rice University, Professor Kang Seoktae of KAIST, Professor Michael Wong of Rice University. Provided by KAIST

On October 30, KAIST announced that Professor Kang Seoktae's research team from the Department of Civil and Environmental Engineering, in collaboration with Professor Kim Gunhan of Pukyong National University, Professor Michael S. Wong's team at Rice University, as well as researchers from the University of Oxford, Lawrence Berkeley National Laboratory, and the University of Nevada, has developed a new technology that rapidly adsorbs and removes PFAS from water.

PFAS are a group of chemical compounds consisting of carbon (C) and fluorine (F) bonds. Due to their excellent insulating and heat-resistant properties, they are widely used in various industries, including non-stick pan coatings, waterproof clothing, lubricants, semiconductor manufacturing, and military and aerospace equipment.

However, PFAS released into the environment during use and disposal contaminate soil, water, and air, and are known to accumulate in the human body through food and air.

In fact, a 2020 study found that PFAS concentrations exceeded environmental standards in 45% of tap water in the United States and over 50% of rivers in Europe. The problem is that PFAS accumulated in the human body are rarely excreted and can cause a range of health issues, including weakened immunity, dyslipidemia, impaired growth, and kidney cancer.

For these reasons, the European Union has gradually banned the use of PFAS across all industries, and the United States has made it mandatory for manufacturers and importers to report PFAS usage starting in 2023.

Last year, the drinking water standards for PFOA (perfluorooctanoic acid) and PFOS (perfluorooctanesulfonic acid) were tightened to 4 parts per trillion (ppt). This means that even just 4 trillionths of a gram of these substances per liter of water exceeds the standard, indicating that even trace amounts can be harmful to humans.

The PFAS purification process generally involves two steps: first, adsorbing and concentrating the contaminated water, and then decomposing the PFAS through photocatalytic or advanced oxidation processes.

However, until recently, the lack of suitable adsorbents resulted in very low purification efficiency. Both activated carbon and ion-exchange resins have limitations in terms of adsorption speed and capacity.

In contrast, the joint research team developed a new material that can rapidly adsorb up to 1,000 times more PFAS than conventional activated carbon or ion-exchange resins. This material, a clay-like substance composed of copper and aluminum (Cu-Al layered double hydroxide, LDH), can effectively adsorb and extract PFAS from water in a short period of time.

KAIST also emphasized that this material can be reused multiple times through thermal or chemical treatment, making it a sustainable purification technology from an environmental perspective.

This research was led by Professor Kim Gunhan of Pukyong National University (first author and corresponding author), Dr. Jung Myungkyun, a postdoctoral researcher at Rice University (co-first author), and Professor Kang Seoktae of KAIST (corresponding author). The results were recently published as a cover article in the international journal 'Advanced Materials.'

This content was produced with the assistance of AI translation services.