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The Effect of Adsorption on Sulfate Leaching
Author(s) -
Bolan N. S.,
Scotter D. R.,
Syers J. K.,
Tillman R. W.
Publication year - 1986
Publication title -
soil science society of america journal
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.836
H-Index - 168
eISSN - 1435-0661
pISSN - 0361-5995
DOI - 10.2136/sssaj1986.03615995005000060009x
Subject(s) - adsorption , leaching (pedology) , freundlich equation , tracer , sulfate , chemistry , effluent , dispersion (optics) , mineralogy , soil science , geology , soil water , environmental engineering , environmental science , organic chemistry , physics , nuclear physics , optics
Movement of sulfate (S) through repacked columns of soil with high and low S adsorption capacity was studied in the laboratory. Differences in movement could be explained by the shape of adsorption isotherms which were determined from batch‐type experiments. 35 S was found to be a suitable tracer to study the movement of applied 35 S. For step‐function changes between 0, 3.12, and 6.24 mol m −3 in the concentration of the applied S solution, different breakthrough curves (BTC) were found for the rising and falling limbs. Also the higher the concentration of S in the applied solution, the earlier the added S appeared in the effluent. The BTC obtained agreed well with those calculated from numerical solution of the dispersion‐convection equation, assuming a Freundlich adsorption isotherm and instantaneous reversible adsorption. However, after leaching of a pulse of S added to the surface soil, the observed S distributions in soil columns were not well described by theory. The discrepancies were largest when the soil containing the added pulse of S was incubated prior to leaching. Possible reasons for this lack of agreement are discussed.