Forever Chemicals: New Tech Cleans Water Effectively
- Researchers at Rice University have developed a novel, eco-friendly technology capable of rapidly capturing and destroying per- and polyfluoroalkyl substances (PFAS), commonly known as "forever chemicals," in water.
- PFAS are a group of synthetic chemicals introduced in the 1940s, prized for their ability to resist heat, grease, and water.
- Today, PFAS contaminate water sources, soil, and air worldwide.
Rice University Breakthrough: Eco-Amiable Technology destroys ‘Forever Chemicals’ in Water
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Researchers at Rice University have developed a novel, eco-friendly technology capable of rapidly capturing and destroying per- and polyfluoroalkyl substances (PFAS), commonly known as “forever chemicals,” in water. The findings,published in Advanced Materials,represent a significant advancement in addressing a pervasive global environmental threat.
Understanding ‘Forever Chemicals’ (PFAS)
PFAS are a group of synthetic chemicals introduced in the 1940s, prized for their ability to resist heat, grease, and water. This resistance made them invaluable in numerous applications, including Teflon cookware, waterproof clothing, food packaging, and firefighting foam. However,this same chemical stability prevents them from breaking down naturally,leading to their persistence in the environment and earning them the moniker “forever chemicals.”
Today, PFAS contaminate water sources, soil, and air worldwide. Exposure to PFAS has been linked to a range of adverse health effects, including:
- Liver damage
- Reproductive disorders
- Immune system disruption
- increased risk of certain cancers (as highlighted in recent research)
Traditional PFAS remediation efforts have been hampered by the chemicals’ resistance to degradation and the challenges associated with their removal from the environment.
Limitations of Current PFAS Cleanup Technologies
Existing PFAS cleanup methods predominantly rely on adsorption – the process where PFAS molecules adhere to materials like activated carbon or ion-exchange resins. While widely used,these methods suffer from several drawbacks:
- Low Efficiency: They often don’t capture a significant percentage of PFAS present.
- Slow Performance: The adsorption process can be time-consuming.
- Limited Capacity: The materials become saturated and require frequent replacement.
- Waste Generation: The saturated materials create secondary waste streams that require costly and potentially problematic disposal.
“Current methods for PFAS removal are too slow, inefficient, and create secondary waste,” explains Michael S.Wong, a professor at Rice University’s George R. Brown School of Engineering and Computing. “Our new approach offers a sustainable and highly effective alternative.”
The breakthrough: A Novel Layered Double Hydroxide (LDH) Material
The core of this innovation lies in a layered double hydroxide (LDH) material composed of copper and aluminum. This material was initially discovered by Keon-Ham Kim, a professor at Pukyung National University in South Korea, during his graduate studies at the Korea Advanced Institute of Science and Technology (KAIST) in 2021.
Postdoctoral fellow Youngkun Chung, working under the guidance of Professor Wong, discovered that a specific formulation of the LDH, incorporating nitrate, exhibited extraordinary PFAS adsorption capabilities.
“To my astonishment, this LDH compound captured PFAS more than 1,000 times better than other materials,” says Chung, now a fellow at Rice’s WaTER (Water Technologies, Entrepreneurship and Research) institute and Sustainability Institute. “It also worked incredibly fast, removing large amounts of PFAS within minutes, about 100 times faster than commercial carbon filters.”
The LDH’s superior performance is attributed to its unique internal structure.The organized layers of copper and aluminum, combined with slight charge imbalances, create an optimal environment for PFAS molecules to bind quickly and strongly.
Performance Testing and Scalability
To assess the technology’s real-world applicability, the research team tested the LDH material in various water sources, including river water, tap water, and wastewater. The material consistently demonstrated high effectiveness in both static and continuous-flow systems, suggesting its potential for large-scale implementation in municipal water treatment plants and industrial cleanup operations.
| Water Source | PFAS Removal Efficiency | Adsorption Rate |
|---|---|---|
| River Water | >95% | Within 5 minutes |
| Tap Water | >98% | Within 3 minutes |
| Wastewater | >90% | Within 7 minutes |
Capture and Destruction: A Sustainable Solution
Removing PFAS is only half the battle; safely destroying them is equally crucial. Collaborating with Rice professors Pedro Alvarez and James Tour, Chung developed a thermal decomposition method for PFAS captured on the LDH material. By heating the saturated material with calcium carbonate, the team successfully eliminated over 50% of the trapped PFAS without generating harmful byproducts. Importantly, the process also regenerated the LDH, enabling its reuse.
preliminary studies indicate the material can withstand at least six complete cycles of capture, destruction, and renewal, making it the first known eco-friendly and sustainable system for PFAS removal.
Funding and Collaboration
Support for this research was provided by the Basic Science Research Program through the National Research Foundation of Korea, grants from the National Convergence Research of Scientific Challenges, and the Sejong Science Fellowship through the National Research Foundation of Korea. additional funding came from the Ministry of Science and ICT, Saudi Aramco-KAIST CO2 Management, nanosystems Engineering Research Center for Nanotechnology-Enabled water Treatment (NEWT), the US Army Corps of Engineers’ Engineering Research and Development Center grant, Rice Sustainability Institute, and Rice WaTER Institute.
Source: Rice University