Comprehensive Nontargeted Analysis of Fluorosurfactant Byproducts and Reaction Products in Wastewater from Semiconductor Manufacturing

Abstract Semiconductor manufacturing employs per- and polyfluoroalkyl substances (PFAS) as fluoroasurfactants to enhance the quality of photolithography lines. Our research, employing a fragment-based approach to investigate nontarget PFAS, overcomes conventional homologous series limitations. We identified 80 PFAS in wastewater and effluent samples from semiconductor industry, including 29 newly discovered compounds, categorized into three groups. First, primary PFAS formulations, such as perfluorobutane sulfonamide and perfluorobutane sulfonamido (di)ethanols, are accompanied by byproducts comprising approximately 0.1% of the total height compared to the main components. These byproducts, which exhibit variations in fluoroalkyl chains such as hydro-substituted, unsaturated, or ether structures, were reported for the first time to exist in commercially authentic standards, indicating their possible origin as byproducts of chemical manufacturing process. Second, transformation products from perfluorobutane sulfonamido ethanol during oxidation, including the first identified intermediate transformation compounds, perfluorobutane sulfonamido acetaldehyde and its hydrate, were obtained. Third, diverse reaction products are generated from the intricate processes of semiconductor manufacturing, which utilize strong acids, bases, and solvents under UV light or heated conditions. These processes include the formation of PFAS-related compounds through hydration, sulfonation, oxidation, and nitrification. This study revealed 22 isomeric PFAS, encompassing headgroup isomers and functional tail group isomers. These findings underscore the importance of comprehending diverse reactions and the overall emission compositions of PFAS in semiconductor wastewater, highlighting its complexity and presenting challenges for subsequent wastewater treatment.