PAH sorption to soil minerals low in or free of organic matter: Kinetics and mechanisms

The processes and properties which control the sorption and kinetics of sorption of PAH (phenanthrene, anthracene, pyrene, BaP, and perylene) to different inorganic soil constituents were elucidated. The decrease in aqueous phase concentration followed the line pyrene < BaP < perylene. This increase corresponded to increasing molecular weight and increasing K_ow values of the PAH. Phenanthrene sorption increased from quartz sand (no sorption) to goethite-coated quartz sand (average amount sorbed: 6%) to quartz sand, montmorillonite mixture (21%). Similar results were also observed for anthracene. Sorption of pyrene was observed for all model sorbents. Sorption was higher for clay minerals and iron oxides than for quartz sand.