Hark Ketelsen, S. Meyer-Windel
Jun 1, 1999
Citations
3
Influential Citations
122
Citations
Quality indicators
Journal
Geoderma
Abstract
The objective of this study was to assess the extent of Brilliant Blue FCF adsorption in soils and to identify soil properties that play a predominant role in adsorption of the dye. Additionally the adsorption kinetics of the dyestuff were investigated. With increasing equilibrium concentration the adsorption converged to a maximum and Langmuir isotherms were fitted to the data. The parameter Qmax of the isotherm was correlated to soil parameters. Spearman rank correlations showed a strong positive correlation between Qmax and clay content and a negative correlation between Qmax and OC content. Iron and aluminium (hydr)oxides had no influence on Brilliant Blue FCF adsorption. The presumption that the dye's adsorption may increase with decreasing pH due to the prevailing neutral form of the molecule is not supported by our data. A regression equation was developed for prediction of maximum Brilliant Blue FCF adsorption in soils using clay and OC contents as independent variables. Achievement of equilibrium progressed in two stages. A fast removal of Brilliant Blue FCF from solution during the first hour is followed by a slower approximation towards equilibrium. The partly considerable adsorption of Brilliant Blue FCF to soils diminishes its suitability for tracing water flow through soils. Comparison of flow properties of soils via stained profiles may lead to inadequate interpretations, due to differing adsorption characteristics of the soils.