HYDRAULIC CONDUCTIVITY OF ORGANOCLAYS AND ORGANOCLAY-SAND MIXTURES TO FUELS AND ORGANIC LIQUIDS

BENSON, CRAIG; JO, HO YOUNG; MUSSO, TELMA BELÉN

JOURNAL OF GEOTECHNICAL AND GEOENVIRONMENTAL ENGINEERING

ASCE-AMER SOC CIVIL ENGINEERS

Año: 2014

1090-0241

Hydraulic conductivity, swelling, and liquid sorption tests were conducted on an organoclay with dimethylammonium bound to the surface using five fuels (No. 1 and 2 fuel oil, diesel, jet fuel, and gasoline), four pure organic liquids (methanol, phenol, ethylbenzene, and dioctyl-phthalate) ranging from hydrophilic to hydrophobic, and Type II deionized (DI) water. The more hydrophilic liquids (methanol, phenol) and DI water resulted in little swelling or sorption and high hydraulic conductivity. The less refined fuels comprised of heavier distillates (fuel oil, diesel) and the phthalate resulted in modest or low swelling and sorption and intermediate to low hydraulic conductivity. The highly refined fuels comprised of lighter distillates and ethylbenzene resulted in high swelling and sorption and very low hydraulic conductivity. Swelling, sorption capacity, and hydraulic conductivity are related monotonically, but none correlates systematically with solubility or octanol-water partition coefficient (parameters describing hydrophobicity). When the swell index is at least 10 mL/2 g, the organoclay has hydraulic conductivity less than 10-10 m/s. Below 10 mL/2 g, the hydraulic conductivity increases rapidly as the swell index decreases. Sand-organoclay mixtures with uniform sand require more organoclay to achieve low hydraulic conductivity and are more sensitive to swell index. At least 50% organoclay is recommended to ensure a mixture has low hydraulic conductivity to gasoline and jet fuel. Diesel and fuel oil can require at least 75% organoclay to achieve low hydraulic conductivity.