Thesis Defense: Analytical development and fate of PFAS in complex matrices: application to wastewater treatment plant and their recovery products
Babatoundé Idjaton successfully defended his doctoral thesis. @Babatoundé Idjaton
The PROMISCES project also includes many doctoral students. One of them, Babatoundé Idjaton, has now successfully defended his doctoral thesis on 18th December 2024, in Paris. The title of the thesis is "Analytical development and fate of per- and polyfluoroalkyl substances (PFAS) in complex matrices: application to wastewater treatment plant (WWTP) and their recovery products". Babatoundé Idjaton was a doctoral researcher in the field of Environmental Analytical Chemistry at Bureau de Recherches Géologiques et Minières and Institut de Physique du Globe de Paris (IPGP).
This thesis aims to investigate PFAS in wastewater and sludge by developing methods to analyze these complex matrices. Targeted HPLC-MS/MS was used for 58 PFAS compounds, while global analysis methods like combustion coupled with ion chromatography (CIC) quantified adsorbable organic fluorine (AOF), extractable organic fluorine (EOF), total organic fluorine (TOF), total fluorine (TF), and inorganic fluorine (IF). TOP Assay was also developed to identify PFAS precursors.
These methods were validated and applied to complex samples, including wastewater and sewage sludge, within PROMISCES samples. The results showed that the complementary of the different methods was highlighted by the high proportion of unknown PFAS (99%) present in the samples despite the 58-compound method. AOF and EOF quantification accounted for a small percentage of TOF (1 to 23%) and TF (0.1 to 2%). The TOP assay allows the quantification of oxidisable PFAS and provided information on the environmental footprint of PFAS precursors but did not close the mass balance between targeted and total analyses. The liquid/solid partitioning of PFAS is highlighted, with the presence of short-chain compounds (C8) in solid samples (sewage sludge, fertilisers). The conversion of sewage sludge to fertilisers leads to a reduction of more than 70% in total fluorine, especially in the 58 PFAS targeted by the study. However, molecules such as PFOA, 6:2 FTSA and EtFOSAA were quantified at least once in the fertilisers.
These results will allow us to propose PFAS monitoring strategies that can be applied to different complex matrices.
Congratulations on passing your doctoral thesis, Babatoundé!