| Title |
Dissolution of Polycyclic Aromatic Hydrocarbons from Complex Mixture in a Contaminated Soil |
| Authors |
염익태 ; 안규홍 ( Ick Tae Yeom ; Kyu Hong Ahn ) |
| Abstract |
Dissolution of PAHs from a mixture of soil and multi-components coal tar was studied in batch experiments. Equilibrium aspects of the release of individual components into water were evaluated by washing the soil/tar mixture with deionized water. Solubilities of PAHs in the mixture were much less than their intrinsic aqueous solubilities. Only a small fraction ($lt;0.1%) of soil-bound PAHs could be dissolved when 100g soil was washed with 1L water. Equilibrium partitioning of PAHs between soil/tar and water could be described by Raoult`s law assuming the tar residues in the soil behave ideally. To investigate kinetic aspects of PAH release from the soil/tar, Tenax - TA, a polymeric adsorbent was used. Tenax adsorb aqueous PAHs completely from solution and thus maximize their mass transfer at the soil/tar - water interface. With Tenax in water, most constituent PAHs failed to attain equilibrium, indicating the release of PAHs from soil/tar mixture is a slow, rate-limiting process. To elucidate the rate- limiting process, both interfacial mass transfer(film diffusion) and matrix diffusion models were tested to fit the observed data. Model analysis revealed the diffusion of PAH through the organic matrix of soil/tar is most likely the process responsible for the slow release of PAHs. |