Qhov sib txawv tseem ceeb ntawm PFAS thiab PFOS yog tias PFAS hais txog ib pawg ntawm cov khoom sib txuas uas muaj ntau yam fluorine atoms txuas rau cov saw hlau alkyl, thaum PFOS hais txog ib tug tswv cuab ntawm pawg PFAS uas muaj cov saw hlau uas muaj 8 carbon atoms.
PFAS yog ib pawg loj ntawm tib neeg tsim cov tebchaw suav nrog PFOS, PFOA, GenX, thiab lwm yam. Lub sij hawm PFAS sawv cev rau cov tshuaj per- thiab poly-fluoroalkyl thaum lub sij hawm PFOS sawv cev rau perfluorooctanesulfonic acid.
PFAS yog dab tsi?
PFAS yog ib- thiab poly-fluoroalkyl tshuaj uas suav nrog cov tshuaj organofluorine uas tsim los ntawm tib neeg. Cov tshuaj sib xyaw no muaj ntau yam fluorine atoms txuas rau alkyl saw. Lub perfluoroalkyl moiety ntawm cov tebchaw yog muab raws li –CnF2n-. Peb tuaj yeem pom ntau dua 4000 tus tswv cuab hauv pawg tshuaj no.
Nws kuj muaj ib pab pawg hu ua fluorosurfactants. Cov tshuaj no muaj fluorinated tail thiab lub taub hau hydrophilic. Tus Tsov tus tw thiab lub taub hau qauv no yog vim li cas rau npe lawv li surfactants. Cov surfactant molecules no muaj txiaj ntsig zoo hauv kev txo qhov nro ntawm dej dua li hydrocarbon surfactant molecules. Feem ntau, fluorosurfactant tuaj yeem txo qhov nro ntawm qhov chaw rau tus nqi uas yog ib nrab ntawm qhov tuaj yeem tau txais los ntawm hydrocarbon surfactants.
Fluorocarbons feem ntau yog lipophilic. Yog li ntawd, cov qauv no nyiam mloog zoo ntawm cov kua-cua interface. Tsis tas li ntawd, cov molecules no tsis dhau London rog, uas yog ib qho tseem ceeb uas yog lub luag haujlwm rau lipophilicity ntawm molecules. Vim lub siab electronegativity ntawm fluorine atoms, lub polarizability ntawm surfactant nto yog txo.
Dhau li ntawm, PFAS muaj lub luag haujlwm tseem ceeb ntawm kev lag luam polymer uas cov tuam txhab xws li DuPont, 3M, thiab lwm yam muaj feem ntau ntawm nws cov ntawv thov. Cov PFASs no yog siv rau hauv cov khoom siv polymer raws li emulsion polymerization.
PFOS yog dab tsi?
PFOS yog perfluorooctanesulfonic acid. Nws yog ib tug tswv cuab ntawm PFAS pawg ntawm cov tshuaj sib xyaw. PFOS yog suav tias yog ib qho anthropogenic fluorosurfactant nrog rau cov pa phem thoob ntiaj teb. Peb tuaj yeem tsim cov khoom siv no los ntawm kev tsim cov khoom siv hluav taws xob, lossis nws cov ntaub ntawv raws li cov khoom lag luam los ntawm degradation ntawm cov ntaub ntawv polymer. Muaj ob txoj hauv kev loj rau kev tsim cov khoom sib xyaw no hauv kev lag luam-teev: electrophilic fluorination thiab telomerization.
Daim duab 01: Tus qauv ntawm PFOS
Cov tshuaj formula ntawm PFOS yog C8F17O3S. Nws yog hydrophobic thiab lipophobic compound zoo ib yam li lwm cov tshuaj fluorocarbon. Tsis tas li ntawd, nws pawg sulfonate ntxiv polarity rau cov molecule no. Peb tuaj yeem soj ntsuam tias cov khoom sib txuas no tshwj xeeb ruaj khov hauv kev lag luam thiab tseem nyob hauv ib puag ncig uas nws ua rau muaj kuab paug. Tsis tas li ntawd, PFOS tuaj yeem txo qhov nro ntawm dej thaum piv rau hydrocarbon surfactants.
Qhov txawv ntawm PFAS thiab PFOS yog dab tsi?
Lub sij hawm PFAS sawv cev rau cov tshuaj per- thiab poly-fluoroalkyl thaum lub sij hawm PFOS sawv cev rau perfluorooctanesulfonic acid. Qhov sib txawv tseem ceeb ntawm PFAS thiab PFOS yog tias PFAS hais txog ib pawg ntawm cov khoom sib txuas uas muaj ntau yam fluorine atoms txuas rau cov saw hlau alkyl thaum PFOS hais txog ib tug tswv cuab ntawm pawg PFAS uas muaj cov saw hlau uas muaj 8 carbon atoms.
Ntxiv mus, qhov ruaj khov ntawm PFAS nws txawv nyob ntawm cov qauv tshuaj thaum PFOS yog qhov ruaj khov heev. Yog li, qhov no kuj yog qhov sib txawv tseem ceeb ntawm PFAS thiab PFOS.
Hauv qab no yog cov lus qhia luv luv ntawm qhov sib txawv ntawm PFAS thiab PFOS.
Summary – PFAS vs PFOS
Lub sij hawm PFAS sawv cev rau cov tshuaj per- thiab poly-fluoroalkyl thaum lub sij hawm PFOS sawv cev rau perfluorooctanesulfonic acid. Qhov sib txawv tseem ceeb ntawm PFAS thiab PFOS yog tias PFAS hais txog ib pawg ntawm cov tebchaw uas muaj ntau yam fluorine atoms txuas rau cov saw hlau alkyl thaum PFOS hais txog ib tug tswv cuab ntawm pawg PFAS uas muaj cov saw hlau uas muaj 8 carbon atoms.
