Key Takeaways:
- Researchers at Rice University have developed a new technology that can quickly trap and break down toxic "forever chemicals" (PFAS) in water.
- The technology uses a layered double hydroxide (LDH) material made from copper and aluminum, which can capture PFAS with high performance and speed.
- The LDH material can remove large amounts of PFAS within minutes, making it 100 times faster than commercial carbon filters.
- The technology has been tested in river water, tap water, and wastewater, and has shown high effectiveness in all three.
- The researchers have also developed a process to thermally decompose PFAS after they are captured on the LDH material, making it possible to destroy the chemicals safely and reuse the material.
Introduction to PFAS and the Problem
Per- and polyfluoroalkyl substances (PFAS) are man-made chemicals that have been used in many everyday products, including Teflon pans, waterproof clothing, and some food packaging. These chemicals have been widely used since the 1940s due to their ability to resist heat, grease, and water. However, this same durability also means that they break down very slowly, earning them the nickname "forever chemicals." PFAS have now spread widely and can be found in water, soil, and air around the world, and research has linked exposure to liver damage, reproductive disorders, immune system disruption, and certain cancers.
The Challenges of Current PFAS Removal Methods
Current methods for removing PFAS from water are often ineffective and inefficient. Many standard approaches rely on adsorption, meaning the chemicals stick to materials such as activated carbon or ion-exchange resins. However, these methods have major limitations, including low efficiency, slow operation, limited capacity, and the buildup of additional contaminated waste that still has to be handled. According to Michael S. Wong, a professor at Rice’s George R. Brown School of Engineering and Computing, "Current methods for PFAS removal are too slow, inefficient and create secondary waste." This highlights the need for a new and more effective approach to removing PFAS from water.
The Breakthrough LDH Material
The new approach developed by the researchers at Rice University is built around a layered double hydroxide (LDH) material made from copper and aluminum. This material was first identified by Keon-Ham Kim, a professor at Pukyung National University in South Korea, in 2021. As the team explored these compounds further, Youngkun Chung, a postdoctoral fellow at Rice University, found that a specific version containing nitrate could adsorb PFAS with unusually high performance. The LDH material has been shown to capture PFAS more than 1,000 times better than other materials, and it works incredibly fast, removing large amounts of PFAS within minutes.
Testing the LDH Material
The researchers tested the LDH material in river water, tap water, and wastewater to see how well it could perform outside the lab. Across all three, the material remained highly effective, and it also performed well in both static tests and continuous-flow setups. This points to possible use in municipal water treatment systems and industrial cleanup. The material’s internal design, with ordered copper-aluminum layers and small charge imbalances, creates a highly favorable surface where PFAS molecules can attach quickly and strongly.
Closing the Loop with PFAS Destruction and Reuse
Capturing PFAS is only half the battle, as the chemicals still need to be destroyed safely. The researchers developed a process to thermally decompose PFAS after they are captured on the LDH material. When the PFAS-loaded material was heated with calcium carbonate, the researchers removed more than half of the trapped PFAS without releasing toxic by-products. The same step also regenerated the LDH, making it possible to use the material again. Early testing showed that the material could go through at least six complete cycles of capture, destruction, and renewal, making it the first known eco-friendly, sustainable system for PFAS removal that combines rapid cleanup with repeated reuse.
International Collaboration and Research Support
The development of this new technology is the result of an extraordinary international collaboration between researchers at Rice University, the Korea Advanced Institute of Science and Technology (KAIST), and Pukyung National University in South Korea. The research was supported by grants from the National Research Foundation of Korea, the Ministry of Science, and the Ministry of Education, as well as funding from Saudi Aramco-KAIST CO2 Management, the U.S. Army Corps of Engineers’ Engineering Research and Development Center, and the Rice Sustainability Institute and Rice WaTER Institute. According to Wong, "We are excited by the potential of this one-of-a-kind LDH-based technology to transform how PFAS-contaminated water sources are treated in the near future."
