Reactive transport experiments of linear alkylbenzene sulfonate in laboratory soil columns

Abstract

Laboratory column experiments aids in the understanding of hydrogeochemistry dynamics of different linear alkylbenzene sulfonate homologues when they interact with different sand/soil proportions. Previously it was necessary to characterize the soil columns with a tracer. In this paper, the method to obtain breakthrough curves for the conductivity and chloride concentration of a tracer is verified, and also permits the calculation of transport parameters with an easy-to-use interface, ACUAINTRUSION. The experimental results obtained for LAS concentration in two columns using the same type of core have demonstrated the reproducibility of the method. In these experiments, LAS sorption is more important for longer alkylic chain homologues, especially for C13LAS that was only detected at very low concentrations in the outlet of the soil column. However, C10LAS is less retained by the soil column due to its lower hydrophobicity. In the two experiments with different sand/agricultural soil proportions, the LAS concentrations values were quite similar, and therefore a higher soil column content seems to have no significant effect on LAS homologue detected levels, even when a high LAS concentration pulse occurs (100 ppm).