Remediation of Per- and Polyfluoroalkyl Substances in Landfill Leachate using PW­₁₂-TiO₂ Photocatalyst

Per- and polyfluoroalkyl substances (PFAS) represent a class of highly durable chemical compounds extensively employed in various industries, owing to the remarkable stability conferred by the carbon-fluorine bond. These compounds, along with their persistent breakdown products, exhibit detrimental environmental impacts with levels exceeding EPA health advisory limits (concentrations at the parts per trillion, ppt) in many publicly owned treatment works (POTW) and high levels of contamination throughout a broad distribution of water bodies and other ecosystems globally. Compounding environmental concerns, studies have established a correlation between certain PFAS compounds and detrimental health effects in both humans and animals, including but not limited to cancer and birth defects.

Our research is focused on harnessing the solar photocatalytic capabilities of titanium dioxide (TiO2) and a novel phosphotungstic acid (PW12) - titanium dioxide complex catalyst for the degradation of PFAS compounds present in wastewater. To mimic real-world scenarios, heptafluorobutyric acid (HFBA) is employed as a model pollutant, and its removal is assessed using both commercially available TiO2 and in-situ synthesized PW12-TiO2 catalysts in conjunction with a solar simulator. The outcomes are quantified via UV-Vis Spectrophotometry and fluoride ion selective electrode analysis, adhering to the EPA Test Method 9214 for monitoring fluoride ion in aqueous samples.