Per- and Polyfluoroalkyl Substances Removal from Water by Plasmonic-Photocatalysis

Project Overview

We have successfully shown photocatalytic decomposition of Per- and Polyfluoroalkyl Substances (PFAS) dissolved in water, by incorporating a layer of aluminum (Al) plasmonic nanostructures on top of a titanium dioxide (TiO₂) thin film photocatalyst. The whole sample is immersed in the solution and illuminated with ultraviolet (UV) light. The plasmonics-induced electromagnetic field enhancement drastically increases photo-absorption and electron-hole pair generation at the catalyst surface, thereby enhancing the redox reactions at the catalyst-water interface that break the dissolved organics into shorter-chain by-products. Our results demonstrate that it is indeed feasible to use plasmonic-photocatalyst to enhance PFAS photodecomposition reactions. With further optimized plasmonics design and improved fabrication methodology, simulation results suggest further rate enhancement is possible.

Mission Impact

Our results position us strongly in attracting external follow-on funding in PFAS mitigation, thereby helping to expand Lawrence Livermore National Laboratory's (LLNL's) water infrastructure program. The success of a plasmonic photocatalyst allows us to greatly enhance our current capabilities in water security and technology. The ability to provide efficient and rapid water purification and recycling helps us meet DOE's and broader national needs for Energy and Resource Security.

Furthermore, we have established new nanosphere lithography capability at LLNL, which can be applied to a range of other important research activities that require low-cost, fast nano-patterning. We have consolidated our earlier relationship and collaboration with Prof. Ryan Baxter at the Chemistry department at University of California, Merced, through his graduate student Ryan Brisbin who will be incorporating this work into his PhD dissertation, and is interested in continuing the collaboration and exploring future career opportunities at LLNL.

Publications, Presentations, and Patents

Lenear, R., A.J. Simon, and Allan S.P. Chang. 2020. "Managing PFAS Pollutants in Water and Wastewater." LLNL Summer Student Poster Symposium, Livermore, CA, 5 August 2020. LLNL-PRES-812914.