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  1. Legacy and emerging per- and polyfluoroalkyl substances (PFAS) are widely detected in environmental and human samples because of their widespread use and resistance to degradation. Due to the increasing concern on health impacts of PFAS resulting from exposure to contaminated water, the development of novel materials to capture and remove PFAS from the environment is needed. Here, we present a self-assembling, fluorinated, zirconium-based metal–organic cage (F-ZrMOC) capable of capturing 37 different PFAS species, at an average of 82% removal from a solution that contains 400 ng/mL of each individual PFAS. The F-ZrMOC captured different classes of PFAS within 30 s, including perfluoroalkyl carboxylates, sulfonates, sulfonamides, ethoxylates, and fluorotelomer carboxylates/sulfonates/alcohols from water during in-vial, static, and flow through exposures (in which the F-ZrMOC is used as a solid phase extraction sorbent). Removal efficiency is higher for PFAS with chain lengths of seven carbons or higher; the presence of complex matrices such as untreated wastewater and groundwater samples did not significantly reduce the removal efficiencies for PFAS. The F-ZrMOC was characterized using 1H and 19F nuclear magnetic resonance (NMR) spectroscopy, and the stoichiometry of the synthesized cage was confirmed using Fourier transform-ion cyclotron resonance mass spectrometry. The surface area and pore size of F-ZrMOC were further determined by N2 and CO2 sorption measurements. 19F-NMR spectroscopy revealed that solvent plays an important role in the capture of PFAS; once the cages are in contact with methanol solution, captured PFAS are released. 
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    Free, publicly-accessible full text available January 26, 2025
  2. We have predicted acid dissociation constants (pKa), octanol–water partition coefficients (KOW), and DMPC lipid membrane–water partition coefficients (Klipid-w) of 150 different eight-carbon-containing poly-/perfluoroalkyl carboxylic acids (C8-PFCAs) utilizing the COnductor-like Screening MOdel for Realistic Solvents (COSMO-RS) theory. Different trends associated with functionalization, degree of fluorination, degree of saturation, degree of chlorination, and branching are discussed on the basis of the predicted values for the partition coefficients. In general, functionalization closest to the carboxylic headgroup had the greatest impact on the value of the predicted physicochemical properties. 
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    Free, publicly-accessible full text available January 12, 2025
  3. Abstract Land application of treated sewage sludge (also known as biosolids) is considered a sustainable route of disposal because it reduces waste loading into landfills while improving soil health. However, this waste management practice can introduce contaminants from biosolids, such as per- and polyfluoroalkyl substances (PFAS), into the environment. PFAS have been observed to be taken up by plants, accumulate in humans and animals, and have been linked to various negative health effects. There is limited information on the nature and amounts of PFAS introduced from biosolids that have undergone different treatment processes. Therefore, this study developed analytical techniques to improve the characterization of PFAS in complex biosolid samples. Different clean-up techniques were evaluated and applied to waste-activated sludge (WAS) and lime-stabilized primary solids (PS) prior to targeted analysis and suspect screening of biosolid samples. Using liquid chromatography with high-resolution mass spectrometry, a workflow was developed to achieve parallel quantitative targeted analysis and qualitative suspect screening. This study found that concentrations of individual PFAS (27 targeted analytes) can range from 0.6 to 84.6 ng/g in WAS (average total PFAS = 241.4 ng/g) and from 1.6 to 33.8 ng/g in PS (average total PFAS = 72.1 ng/g). The suspect screening workflow identified seven additional PFAS in the biosolid samples, five of which have not been previously reported in environmental samples. Some of the newly identified compounds are a short-chain polyfluorinated carboxylate (a PFOS replacement), a diphosphate ester (a PFOA precursor), a possible transformation product of carboxylate PFAS, and an imidohydrazide which contains a sulfonate and benzene ring. 
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