Interactions between crude oil and Patagonian soil as a function of the soil clay-water content

The interactions of crude oil, with soils having different clay and water contents were studied as a function of time, as a contribution to the understanding of the influence that sorption and desorption effects might have in the efficiency and effectiveness of the remediation techniques. Characteristic Patagonian soils have low amounts of organic matter, (usually less than 1%), and high clay contents; therefore, they are convenient media to study the influence of day in sorption, avoiding interactions with organic matter. It was found that addition of clays to the soil changed the rate and extent of the interactions and favored the sorption; linear sorption uptake isotherms were observed. The partition coefficients, K-d, of the different samples are correlated with the clay and water contents in the soil, were the multiparametric equation obtained had a satisfactory predictive value. On the other hand, the data obtained with the different oil fractions are consistent with competitive interactions of the different types of chemical species for accessing to active sites. To evaluate the model, similar studies were carried out,vith simulated samples of known chemical composition. In spite of the complexity of the oil system, results obtained with the simulated samples were consistent with the sorption model. The parameters determined are useful for the design of remediation techniques.