کد مقاله کد نشریه سال انتشار مقاله انگلیسی نسخه تمام متن
4546876 1627071 2012 10 صفحه PDF دانلود رایگان
عنوان انگلیسی مقاله ISI
Assessing the effect of grain-scale sorption rate limitations on the fate of hydrophobic organic groundwater pollutants
موضوعات مرتبط
مهندسی و علوم پایه علوم زمین و سیارات فرآیندهای سطح زمین
پیش نمایش صفحه اول مقاله
Assessing the effect of grain-scale sorption rate limitations on the fate of hydrophobic organic groundwater pollutants
چکیده انگلیسی

Subsurface pollutant transport models accounting for sorption rate limitations are computationally more demanding than those assuming local sorption equilibrium. We combine batch and column tests with modeling for a comparative assessment of different sorption models. For the relatively hydrophobic compound naphthalene, a model assuming local sorption equilibrium was unable to reproduce breakthrough curves in column studies with Canadian River Alluvium sediment which contains carbonaceous particles. Fully calibrated independent forward predictions of a first-order kinetic and two diffusion kinetic sorption models were in much better agreement with the experimental data. Predictions using a diffusion-limited kinetic sorption model assuming concentration-independent sorption coefficients performed equally well as a model using the Freundlich isotherm. Both diffusion-based kinetic sorption models were superior to the first-order rate approach. In the present study, the validity of the local sorption equilibrium assumption is discussed based on a Damköhler number and thus, the compound's sorption properties, the aquifer properties, and the scale of the process. Relatively high groundwater velocities in combination with a low sorption coefficient Kd and slow diffusion limited sorption kinetic rates are necessary conditions to justify the implementation of grain-scale sorption rate limitations in groundwater contaminant fate models. Such conditions exist when a low amount of carbonaceous particles is present in aquifers with high permeability.


► A comparative assessment of different sorption models using column experimental results.
► Both diffusion-based kinetic sorption models were superior to the first-order rate approach.
► The validity of the local sorption equilibrium assumption is discussed based on the Damköhler number.
► Grain-scale sorption kinetics are relevant for high permeability aquifers with a low amount of carbonaceous particles.

ناشر
Database: Elsevier - ScienceDirect (ساینس دایرکت)
Journal: Journal of Contaminant Hydrology - Volumes 129–130, 15 March 2012, Pages 70–79
نویسندگان
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