Colloidal transport and agglomeration in column studies for advanced run-off filtration facilities--particle size and time resolved monitoring of effluents with flow-field-flow-fractionation.
The efficiency of road run-off filtration facilities based on ion-exchange materials is reduced by pollutants which are transported bound to particles. To quantify the factors governing particle transport phenomena, a simplified model consisting of quartz sand-filled columns representing the filter/soil was set up. Suspensions of artificial clays, cold water-extracted natural clays, and real run-off were used as model effluents. Five experiments were performed: breakthrough of a natural soil suspension, remobilization of a natural soil suspension after ionic strength-drop, the same two experiments with a suspension of the artificial clay mineral Laponite, and the remobilization of run-off accumulated on a column at high ionic strength with an ionic strength down-gradient. Short-interval effluent fractions were analysed by flow-field-flow-fractionation (F4) to obtain the size distributions of the colloids present. The size distributions of subsequent fractions were then plotted in a staggered arrangement to give three-dimensional graphs that are time- and particle size-resolved. With this method the subsequent release of different agglomerate sizes formed on the column could be shown for the artificial clay mineral, questioning its use as a model colloid. The combined particle size- and time-resolved plots proved to be a powerful tool for monitoring colloidal solids in column effluents.
Siepmann
R
R
Technical University Hamburg Harburg, Dept of Environmental Science and Technology, D-21073 Hamburg. siepmann@tu-harburg.de
von der Kammer
F
F
Förstner
U
U
D002852:Chromatography, Ion Exchange / Q000379:methods*; D003102:Colloids / Q000737:chemistry*; D005374:Filtration; D010316:Particle Size; D016062:Porosity; D011891:Rain; D012212:Rheology; D014867:Water / Q000737:chemistry; D014872:Water Movements; D014873:Water Pollutants / Q000032:analysis*
D003102:Colloids; D014873:Water Pollutants; D014867:Water