Removal of polycyclic aromatic hydrocarbons from water by migration into polyethylene

Water was spiked with three polycyclic aromatic hydrocarbons (PAHs) and filled into a steel diffusion chamber. Low-density polyethylene sheet combined of five polyethylene foils was used as a partition in the chamber. Depth of PAHs migration into the sheet was followed for 143 h, using high performance liquid chromatography with selective fluorimetric detection after extraction of PAHs from the foils peeled off. On the basis of the results obtained, the process of PAHs migration into PE was characterised as a one-dimensional diffusion into polyethylene bulk. The diffusion coefficients were calculated for individual compounds using the second Fick law. It was concluded that PAHs are primarily adsorbed on the polyethylene surface with subsequent migration into bulk polymer. Transportation of PAHs through the bulk can be described satisfactorily by Fickian laws of diffusion and is consistent with the theory of the depth adsorption of PAHs in polyethylene.