Objective

The occurrence of per- and polyfluoroalkyl substances (PFAS) in the environment, coupled with their known adverse effects on public health, has been recognized as an emerging issue. Adsorption using carbon-based sorbents is the most widely applied approach for removing PFAS from impacted water. Specifically, thermal regeneration of carbon-based sorbents is a common practice. However, this practice lacks knowledge and information on PFAS residues and their byproducts that may remain in the reactivated materials. The project aims to develop an innovative and cost-effective hydrothermal technology to destroy PFAS adsorbed on designer biochars, while at the same time reactivating the spent sorbents. The specific objectives include the following:

  • Generate low-cost designer biochars to efficiently adsorb PFAS from impacted water;
  • Develop a low-energy hydrothermal treatment system for the complete destruction of PFAS adsorbed on the designer biochar and explore the defluorination and decomposition processes and mechanisms of PFAS; and
  • Reactivate PFAS-laden designer biochars without altering the long-term effectiveness of the sorbents.

Technical Approach

This project will conduct a series of laboratory experiments to develop an innovative and low-energy hydrothermal technology to destruct PFAS bound onto designer biochars while at the same time reactivating the spent sorbents. The experiments will also provide valuable information to improve the understanding of the fate of PFAS related to the innovative remedial technology. The tasks and methods include:

  • Optimize the production conditions to generate the most efficient and cost-effective designer biochars from biomass pretreated with lime sludge to adsorb PFAS from water;
  • Conduct sorption experiments to investigate sorption kinetics and capacities of designer biochars and thereby select the most efficient and cost-effective sorbents for PFAS removal;
  • Develop a subcritical hydrothermal liquefaction system for the complete destruction of PFAS adsorbed on the designer biochars;
  • Explore the defluorination and decomposition processes and mechanisms of PFAS during hydrothermal regeneration of spent designer biochars;
  • Reactivate the spent designer biochars using the hydrothermal treatment and assessing their long-term sorption effectiveness;
  • Scale up this novel PFAS remedial technique by developing a continuous flow hydrothermal system; and
  • Perform techno-economic analysis and environmental benefit analysis for the technology.

Benefits

This project will provide novel and cost-effective sorbents to remove PFAS from impacted water and offer an innovative and low-energy hydrothermal technique to destroy PFAS bound onto designer biochars, while at the same time reactivating the spent sorbents. It will also provide a detailed and systematic approach to assess the PFAS destruction process and mechanism under hydrothermal treatment. The results and knowledge gained from the project will provide useful and much needed information to improve the understanding of remedial technologies for carbon-based sorbents laden with PFAS. The successful completion of this research will help the Department of Defense, other federal and state agencies, and/or the scientific community to improve their management strategies on PFAS resulting from the use of aqueous film-forming foam. (Anticipated Project Completion - 2026)

  • PFAS,

  • Thermal destruction of PFAS contaminated media,