fbpx
Skip to content
Grantees
|

Kinetic Evaluation of the Thermal Decomposition of Per- and Polyfluoroalkyl Substances in Waste Management Systems

Investigators: Florention B. Dela Cruz & Linda Lee, University of North Florida

Start Date: 2025

Amount: $130,000

Project Duration: 2 years

Proposal Justification & Objectives

Facilities responsible for managing and disposing of solid waste accept a variety of materials containing per- and polyfluoroalkyl substances (PFAS), commonly found in discarded consumer products. Evaluating the fate and transformations of PFAS in thermal systems is crucial for several reasons. First, about 11% of municipal solid waste (MSW) generated in the U.S. is processed by waste-to-energy (WTE) facilities, and the presence of PFAS and products of incomplete combustion (PICs) in combustor ash underscores the need for further investigation. Second, most technologies for PFAS removal involve separation processes, which generate residuals concentrated with PFAS. Optimizing existing thermal processes requires a thorough understanding of the kinetics under field-relevant conditions. However, the effectiveness of thermal treatment processes in destroying PFAS, along with the potential formation of byproducts (e.g., PICs), is not well understood, primarily due to the lack of fully developed and tested source sampling and analytical methods. In this proposed work, we will study the thermal decomposition of PFAS most relevant to the waste management industry, such as fluorotelomer alcohols (FTOHs), which dominate landfill gas. We will conduct a comprehensive analysis of PFAS to enable F-mass balance, characterize the thermal decomposition products, and evaluate the kinetic parameters that govern the process, providing valuable insights for the design and optimization of thermal systems. The overall objective of this proposal is to evaluate the kinetic characteristics of PFAS during thermal decomposition.

The specific objectives are:

  • Identify the major products released during thermal decomposition of PFAS at field-relevant
    conditions.
  • Characterize kinetic parameters associated with the thermal decomposition of major PFAS
    such as, specific rate constant (𝑘), reaction order and activation energy (𝐸a).
  • Evaluate the performance of catalysts ZnAl₂O₄ and CaO for the complete destruction
    of PFAS.
  • Model the decomposition of PFAS in select thermal destruction system (e.g., landfill gas
    flare).

Description of Research Approach

To achieve our objectives, our research approach consists of four tasks: (Task 1) assessing the thermal decomposition products of various PFAS, (Task 2) evaluating the thermal decomposition kinetics of each PFAS and their mixtures, (Task 3) assessing the effectiveness of ZnAl₂O₄ (Al_III) and CaO in achieving complete PFAS destruction, and (Task 4) modeling a flare using the kinetic parameters developed in the study. By the end of the study, we will have gained a deeper understanding of PFAS behavior in thermal systems and will be able to recommend ways to improve the destruction efficiency of existing systems.