Absorption Characterization and the Identification of Factors Influencing Five Organophosphate Esters in Water-Soil System

Abstract

In this study, the absorption behavior of five organophosphate esters (OPEs) congeners was monitored in a water-soil system, and three absorption isotherm equations were modeled. Furthermore, the factors influencing the absorption process including temperature and dissolved organic carbon (DOC) were also investigated. The results showed that an equilibrium state was reached after 12 hours of absorption for these five OPEs congeners, which could be appropriately modeled by the Freundlich isotherm equations with R2 values ranging from 0.963 to 0.995. Significant correlations were observed among the Kd (partitioning coefficient) values and similar chemical structures of OPEs. The Kd values decreased with increasing temperature, indicating the significant role played by temperature. TBEP and TDCP were highly impacted by the DOC content, and for the other OPEs congeners, no clear tendency in Kd values was found with increasing of DOC content.