Henry’s Constants of Persistent Organic Pollutants by a Group-Contribution Method Based on Scaled-Particle Theory

A group-contribution method based
on scaled-particle theory was
developed to predict Henry’s constants for six families of
persistent organic pollutants: polychlorinated benzenes, polychlorinated
biphenyls, polychlorinated dibenzodioxins, polychlorinated dibenzofurans,
polychlorinated naphthalenes, and polybrominated diphenyl ethers.
The group-contribution model uses limited experimental data to obtain
group-interaction parameters for an easy-to-use method to predict
Henry’s constants for systems where reliable experimental data
are scarce. By using group-interaction parameters obtained from data
reduction, scaled-particle theory gives the partial molar Gibbs energy
of dissolution, Δg̅2, allowing
calculation of Henry’s constant, H2, for more than
700 organic pollutants. The average deviation between predicted values
of log H2 and experiment is 4%. Application of an approximate
van’t Hoff equation gives the temperature dependence of Henry’s
constants for polychlorinated biphenyls, polychlorinated naphthalenes,
and polybrominated diphenyl ethers in the environmentally relevant
range 0–40 °C.