Sorption of light hydrocarbons on clays from the Oligocene Kiscell Clay Formation, Hungary

Clays from Solymár (Hungary) were treated with volatile components of light hydrocarbon in order to investigate their ability to sorb these organic compounds. The clays were characterized using XRD, optical microscopy (thin sections) and CEC measurements. The contaminated samples were analyzed using ATD-GC-MS, Rock Eval and XRD. Volatilization of the fluid phase hydrocarbon was monitoring for 663 days. The quantity of volatilized hydrocarbon compounds reached 50.0-65.0% at the end of the experiment. All of the analyses indicate hydrocarbon pollution of the clay layers after the volatilization process. The gross compositions of the fluid and the sorbed phases are different; the total amount of cycloalkanes among the sorbed hydrocarbons is very low. The dominant sorbed components are toluene, xylenes, nC₉, nC₁₀, nC₁₁ and nC₇. Cyclohexane, methylcyclohexane, benzene, nC₁₂ and nC₁₃ also occur in lower concentrations. The geochemical and XRD results indicate that adsorption onto the external surfaces of the clay minerals was the main sorption process.