Abstract
The aggregation behavior of typical aromatic pollutants in the n-octanol phase and its influence on the n-octanol-air partition coefficient (K(OA)) were investigated using molecular dynamics simulation. The aggregate proportion of selected aromatic pollutants gradually increased with increasing simulation time and then reached a dynamic equilibrium state. It is interesting to find that the higher the concentration of aromatic pollutants, the more aggregates formed in the n-octanol phase. Log K(OA) values of these aromatic pollutants were subsequently estimated based on the percentages of aggregates and the solvation free energy from the gas phase to the n-octanol phase. The log K(OA) values were also found to gradually increase with increasing concentration. Therefore, the effect of concentration on K(OA) should be taken into consideration during the analysis of the environmental behavior and transport of these aromatic pollutants. In addition, it was found that π-π interactions drive the formation of different numbers of aggregates for different aromatic pollutants, a phenomenon that affects the K(OA) values of aromatic pollutants. The above results shed some light on the effects of aggregates and concentration on the partition behavior of aromatic pollutants and provide a theoretical basis for the correction of K(OA) of aromatic pollutants in the environment.