THE USE OF MODIFIED BENTONITE FOR REMOVAL OF AROMATIC ORGANICS FROM CONTAMINATED SOIL

This study investigates the clay-aromatic interactions with a view to the use of bentonite clay for binding benzene, toluene, ethylbenzene, and o-xylene (BTEX compounds) in contaminated soils. BTEX compounds ar e the most toxic aromatic constituents of gasoline present in many und erground storage tanks. Modified (organophilic) and ordinary bentonite s are used to remove these organics. The organophilic bentonites are p repared by replacing the exchangeable inorganic cations present in ben tonite particles with a quaternary ammonium salt. Various clay-to-soil ratios were applied to determine the efficiency of the modified bento nite in enhancing the cement-based solidification/stabilization (S/S) of BTEX contaminated soils. Toxicity characteristics leaching procedur e (TCLP) tests were performed on soil samples to evaluate the leaching of the organics. In addition, X-ray diffraction analyses were conduct ed to assess the changes in the basal spacing of the clays as a result of their interaction with BTEX compounds. The findings of this study reveal that organophilic bentonite can act as a successful adsorbent f or removing the aromatic organics from contaminated soil. Thus, this m aterial is viable for enhancing the performance of cement-based SIS pr ocesses, as an adsorbent for petroleum spills, and for landfill liners and slurry walls. (C) 1997 Academic Press.