ADSORPTION OF HYDROCARBONS BY CLAY-MINERALS FROM GASOLINE

Adsorption of six hydrocarbons (BTEXs - benzene, toluene, ethylbenzene, p-xylene, m-xylene, and o-xylene) from gasoline by three clay minerals (montmorillonite, illite and kaolinite) was studied using the batch equilibrium method. The clays were treated to remove organic matter before use. Four concentrations of gasoline (10, 50, 100, 150 mul/l) in water were used to get a range in concentration of the BTEXs (0.22-10.65 mul/l). Freundlich adsorption coefficient (K) for each hydrocarbon was consistently higher with montmorillonite than with illite and kaolinite. The presence of competing species resulted in a decrease of K values for toluene from 2.42 from a single solute, to 0.81 for the hydrocarbons mixture (containing benzene + toluene + xylenes) and to 0.69 for gasoline.