What Is PFAS (per- and polyfluoroalkyl substances)?
PFAS means per- and polyfluoroalkyl substances, a large family of synthetic chemicals built around carbon chains containing many carbon-fluorine bonds. These bonds are unusually strong, with a typical bond energy near E_CF = 544 kJ/mol. That high bond strength helps explain why many PFAS resist heat, water, oils, microbes, and ordinary chemical breakdown. The same stability that makes them useful in coatings and foams also makes them persistent contaminants.
In real systems, PFAS move through water, soil, air, and living tissue according to chain length, charge, polarity, and surface activity. Some forms accumulate at interfaces, while others travel readily through groundwater. In advanced water treatment chemistry, their molecular size and electronic structure both affect how well filters, sorbents, or membranes can remove them.
The concept matters because PFAS link molecular design to long-term environmental exposure. Understanding their chemistry helps engineers choose treatment methods, regulators set limits, and scientists evaluate toxicity, mobility, and industrial degradation pathways accurately.
Used in devices include fuel-resistant seals, nonstick coatings, firefighting foams, filtration membranes, and electronics manufacturing materials that require low surface energy or chemical resistance.
Example:
In contaminated groundwater, a charged PFAS molecule can pass through ordinary treatment stages unless a sorbent, membrane, or destructive process targets its chemical structure.
Related Terms:
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