Sustainable per- and polyfluoroalkyl substances contaminated soil remediation: Evaluating the potential of thermal desorption

Per- and polyfluoroalkyl substances (PFASs) have been extensively utilized in various industries. These artificial compounds pose significant environmental and health concerns as they exhibit persistence in soil over long periods and can migrate through soil and groundwater. One potential method for addressing PFASs toxicity is thermal desorption, although its efficacy in calcareous soil remains understudied. In this experimental investigation, we aimed to evaluate the effectiveness of thermal desorption in removing PFASs from two types of calcareous soil: spiked clay and sandy clay loam soil. PFASs were spiked into soil samples, which were subsequently freeze-dried and homogenized. The samples underwent thermal desorption, followed by extraction and analysis of remaining PFASs concentrations using UPLC MS/MS. The study examined the impact of different temperatures, times, and soil types on PFASs removal. Results revealed that the removal fraction of PFASs increased with higher temperatures, although the specific effect varied depending on the soil type and the characteristics of the PFASs. Optimal PFASs removal occurred within the temperature range of 350 to 450°C, with a treatment time of 40 to 60 min. ANOVA analysis indicated a significant interaction between temperature and time, highlighting the influence of temperature on PFASs desorption. The correlation coefficient demonstrated a negative relationship between temperature and PFASs removal from the soil sample. This study successfully demonstrated the effectiveness of thermal desorption in removing PFASs from calcareous soils. The findings contribute to the development of effective strategies for mitigating the environmental and health risks associated with PFASs contamination in soil.