Autor: Th. J. S. Keijzer, P. F. Middeldorp, J. P. G. Loch, P.R. van der Linde, M. M. A. van Alphen
Rok vydání: 2002
Předmět:
Zdroj: Water, Air, and Soil Pollution. 136:361-385
ISSN: 0049-6979
DOI: 10.1023/a:1015247311769
Popis: Desorption of eight polycyclic aromatic hydrocarbons (PAH) fromtwo harbour sludges from the Port of Rotterdam, the Netherlands,was studied by column elution experiments. When water moves in a sludge layer desorbing contaminants like PAH can be dispersedin the environment. Separation of liquid and solid phase inbatches of sludge, stored for more than three years, by ultra-centrifugation at 4 °C yielded equilibrium partition coefficients. Temperature effects could not account for the observed differences with reported literature values. The differences are attributed to the contact time of PAH in thesediment. Laboratory data reported in the literature were oftenobtained after short contact times and therefore may not represent equilibrium partitioning. Our values represent contacttimes in excess of three years and are therefore more representative for the field conditions. Partition coefficientsobtained from column elution experiments were slightly above those obtained from the batch experiments. During column elutionof the sludge from the Beneden Merwede sorption equilibriumwas absent for the lighter compounds. This is attributed to the presence of a large portion of immobile water in the columns. Elution in the Beerkanaal columns occurred at near sorption equilibrium although pore water velocities were higher. Assumingthat desorption is diffusion controlled, observed desorption inboth materials could be explained. The non-equilibrium desorptionin the Beneden Merwede sludge for phenanthrene, and to alesser extent for anthracene and fluoranthene, could be describedby a diffusion limited model assuming spherical particles.
Databáze: OpenAIRE
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