Mass transfer of polyaromatic hydrocarbons (PAHs) in a two-liquid-phase system

Studies were conducted to observe the solubility of phenanthrene, anthracene, and pyrene in four water-immiscible liquids (WILs) and the mass transfer of PAH in a two-liquid-phase (TLP) system. The order of solubility in WILs for three different PAHs was phenanthrene > pyrene >> anthracene. Among the WILs tested in a TLP system, paraffine oil did not affect the mass transfer of three PAHs, while silicone oil reduced the mass transfer of anthracene significantly because paraffine oil had a higher solubilizing capacity for anthracene than silicone oil. When initial PAHs concentration increased up to 2500 mg PAHs/kg soil, the mass transfer of phenanthrene and pyrene were hardly influenced, while that of anthracene was reduced to 40%. As the amount of light paraffine oil decreased, the mass transfer of anthracene decreased significantly compared to that of phenanthrene and pyrene. Based on the present results, it was confirmed that the mass transfer of PAHs from soil to WIL was governed mainly by the solubilizing capacity of WIL for PAHs. This is the first report on the mass transfer of PAHs from soil to WIL, in which the mechanism of TLP process can be understood more clearly.