In silico investigation of gas/particle partitioning equilibrium of polybrominated diphenyl ethers (PBDEs)

- A temperature-dependent QSPR model is developed for KP of PBDE congeners.
- The dispersion, electrostatic and hydrogen bond interactions control the KP of PBDEs.
- Increasing ambient temperature can greatly decrease the log KP values of PBDEs.
- The model can predict the KP values of PBDE congeners under 10-30 °C.

Polybrominated diphenyl ethers (PBDEs), a group of typical brominated flame retardants (BFRs), have drawn an increasing concern due to their widespread manufacture, usage and disposal around the world and the frequent detection in a variety of environmental media. In the present study, we investigated the molecular mechanism of the partitioning equilibrium of PBDEs between gas and atmospheric particles, and developed a new temperature-dependent predictive model for the gas/particle partition coefficient (KP) of these chemicals. Quantum chemical computations were implemented at B3LYP/6-31G (d,p) level of theory based on the neutral electronic ground state of PBDE congeners by Gaussian 09 software package. The model performance was assessed by different validation strategies and the application domain was defined by Williams Plot. Mechanism analysis indicated that the interactions of dispersion, electrostatic and hydrogen bond play crucial roles in the partitioning of PBDEs between the two phases. The developed model can be used to estimate the KP values of PBDEs for which experimental measurements are restricted. Therefore, this work provides an alternative method in a regulatory context of PBDEs.