Title of article :
Role of pH in partitioning and cation exchange of aromatic amines on water-saturated soils
Author/Authors :
Hui Li، نويسنده , , Linda S. Lee، نويسنده , , Jose R. Fabrega، نويسنده , , Chad T. Jafvert، نويسنده ,
Issue Information :
روزنامه با شماره پیاپی سال 2001
Pages :
9
From page :
627
To page :
635
Abstract :
Predicting the reversible interactions between aromatic amines and soil is essential for assessing the mobility, bioavailability and exposure from contaminated sites. Reversible sorption mechanisms of aniline and α-naphthylamine were investigated by using single and binary solute sorption to five soils at several pH values, and by applying a distributed parameter (DP) model. The DP model assumes linear partitioning of the neutral species into soil organic matter domains and organic cation binding on negative-charged sites with the exchange coefficients represented by a Gaussian probability distribution. Sorption nonlinearity was attributed to cation exchange with varying site affinities, which was adequately simulated using the DP model. Greater uptake by hydrophobic partitioning and selectivity for cation exchange sites was observed for α-naphthylamine compared to aniline. Sorption of α-naphthylamine was not impacted quantitatively by aniline under those conditions examined; however, aniline sorption was reduced by α-naphthylamine with the largest reduction occurring in the soil with the lowest pH. DP model simulations showed that although hydrophobic partitioning increases with soil–solution pH, cation exchange still contributes significantly to the total sorption even at soil–solution pH values greater than pKa+2.
Keywords :
Partitioning , Competitive sorption , Speciation , Aromatic amine , Cation exchange , Distributed parameter model
Journal title :
Chemosphere
Serial Year :
2001
Journal title :
Chemosphere
Record number :
735599
Link To Document :
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