More than 5000 types of PFAS have been produced and used for various domestic and industrial applications. However, the most studied PFAS and usually the primary indicators of the wide range of PFAS in the environment are PFOS, PFOA and PFH xS (Perfluorohexane sulfonate ). This is due to the ubiquity of these types of PFAS in the environment due to use in Aqueous Film- Forming Foam (AFFF).
|
Property |
PFOS (potassium salt) |
PFOA (free acid) |
PFHxS |
|
Chemical name |
Perfluorooctane sulfonate |
Perfluorooctanoic acid |
Perfluorohexane-1-sulfonic acid |
|
CAS number |
2795-39-3 |
335-67-1 |
355-46-4 |
|
Molecular formula |
C 8 F 17 SO 3 - K + |
C 8 HF 15 O 2 |
C 6 F 13 SO 3 H |
|
Structural formula |
|
|
|
|
Physical description (physical state at room temperature and atmospheric pressure) |
White powder |
White powder / white waxy solid |
Solid white powder for PFHxS -K |
|
Molecular weight (g / mol ) |
538.23 |
414.07 |
400.11 |
|
Specific weight |
2.05 |
1.7 |
Not found |
|
Melting point (° C) |
> 400 |
45–54 |
41 |
|
Boiling point (° C) |
No data |
189–192 |
238–239 |
|
Vapor pressure a (Pa ) |
3,31 × 10 −4 (20 ° C) |
69 (25 ° C) |
58.9 |
|
Water solubility at 25 ° C (mg / l) |
550-570 (pure water), 370 (fresh water), 25 filtered (sea water) |
9500 (pure water) |
1400 |
|
Henry's law (pure water) constant (atm.m 3 / mol ) |
3,05 × 10 −9 |
It is not possible to measure |
It is not possible to measure (dissociated into the environment) |
|
Organic carbon-water partition coefficient (log K OC) |
2.57 (estimated based on the anion) |
2.06 |
2.05 and 2.4 (measured) and 1.8-2.76 (based on field) |
|
Half life |
Atmosphere: 114 days Water:> 41 years (at 25 ° C) |
Atmosphere: 90 days a Water:> 92 years (at 25 ° C) |
Not found |
