@misc{AhmedMartienssenBryantetal., author = {Ahmed, Naveed and Martienssen, Marion and Bryant, Isaac Mbir and Vione, Davide and Bruzzoniti, Maria Concetta and Riedel, Ramona}, title = {Investigation on UV Degradation and Mechanism of 6:2 Fluorotelomer Sulfonamide Alkyl Betaine, Based on Model Compound Perfluorooctanoic Acid}, series = {ChemEngineering}, volume = {8}, journal = {ChemEngineering}, number = {2}, issn = {2305-7084}, doi = {10.3390/chemengineering8020032}, abstract = {The UV treatment of 6:2 FTAB involves the mitigation of this persistent chemical by the impact of ultraviolet radiation, which is known for its resistance to environmental breakdown. UV treatment of PFOA and/or 6:2 FTAB, and the role of responsible species and their mechanism have been presented. Our investigation focused on the degradation of perfluorooctanoic acid (PFOA) and 6:2 fluorotelomer sulfonamide alkyl betaine (6:2 FTAB, Capstone B), using UV photolysis under various pH conditions. Initially, we used PFOA as a reference, finding a 90\% decomposition after 360 min at the original (unadjusted) pH 5.6, with a decomposition rate constant of (1.08 ± 0.30) × 10-4 sec-1 and a half-life of 107 ± 2 min. At pH 4 and 7, degradation averaged 85\% and 80\%, respectively, while at pH 10, it reduced to 57\%. For 6:2 FTAB at its natural pH 6.5, almost complete decomposition occurred. The primary UV transformation product was identified as 6:2 fluorotelomer sulfonic acid (6:2 FTSA), occasionally accompanied by shorter-chain perfluoroalkyl acids (PFAAs) including PFHpA, PFHxA, and PFPeA. Interestingly, the overall decomposition percentages were unaffected by pH for 6:2 FTAB, though pH influenced rate constants and half-lives. In PFOA degradation, direct photolysis and reaction with hydrated electrons were presumed mechanisms, excluding the involvement of hydroxyl radicals. The role of superoxide radicals remains uncertain. For 6:2 FTAB, both direct and indirect photolysis were observed, with potential involvement of hydroxyl, superoxide radicals, and/or other reactive oxygen species (ROS). Clarification is needed regarding the role of 𝑒-𝑎𝑞 in the degradation of 6:2 FTAB.}, language = {en} } @misc{AhmedMartienssenBryantetal., author = {Ahmed, Naveed and Martienssen, Marion and Bryant, Isaac Mbir and Vione, Davide and Bruzzoniti, Maria Concetta and Riedel, Ramona}, title = {Investigation on UV Degradation and Mechanism of 6:2 Fluorotelomer Sulfonamide Alkyl Betaine, Based on Model Compound Perfluorooctanoic Acid}, series = {ChemEngineering}, volume = {8}, journal = {ChemEngineering}, number = {2}, issn = {2305-7084}, doi = {10.3390/chemengineering8020032}, language = {en} }