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Per- and polyfluoroalkyl substances (also PFAS, [1] PFASs, [2] and sometimes referred to as "forever chemicals" [3] [4]) are a group of synthetic organofluorine chemical compounds that have multiple fluorine atoms attached to an alkyl chain; there are 7 million such chemicals according to PubChem. [5]
It is used as a surfactant and protective coating in applications such as aqueous firefighting foams, textile coating, metal plating and in polishing agents. [ 5 ] [ 6 ] PFHxS production is slowly being phased out since 3M stopped producing C 6 fluorotelomers in 2002, but production by other companies may be ongoing. [ 4 ]
Trifluoroacetic acid is a widely employed acid, used for example in the synthesis of peptides.Its esters are useful in analytical chemistry. Longer-chain perfluoroalkyl carboxylic acids, e.g. with five to nine carbons, are useful fluorosurfactants and emulsifiers used in the production of polytetrafluoroethylene (Teflon) and related fluoropolymers.
Remediation of per- and polyfluoroalkyl substances refers to the destruction or removal of per- and polyfluoroalkyl substances (PFASs) from the environment. PFASs are a group of synthetic organofluorine compounds, used in diverse products such as non-stick cookware and firefighting foams, that have attracted great concern as persistent organic pollutants.
Perfluorobutanoic acid (PFBA) is a perfluoroalkyl carboxylic acid with the formula C 3 F 7 CO 2 H. As the perfluorinated derivative of butyric acid , this colourless liquid is prepared by electrofluorination of the corresponding butyryl fluoride.
Its use contributes to increasing the efficiency of the whole plant. [ 7 ] PFA is also used to make sampling equipment in analytical chemistry and for geochemical or environmental in situ studies in the field, when it is particularly important to avoid chemical contamination from metallic ions at trace levels.
A Stanford research center found more than 1,000 illegal images depicting child sexual abuse in a database used to train image-generation tools like Stable Diffusion.
October 2003 A report by Oregon State University's Jennifer Field which was based on "data on fluorosurfactants in groundwater at three military sites where AFFF was used to train fire responders" concluded that the "perfluoroalkyl sulfonates and perfluoroalkyl carboxylates found in the groundwater came from PFOS-based AFFF agents". [44]