Adsorption of Hazardous Petroleum Constituents by Ordinary and Modified Bentonites

Hazardous chemicals are the major cause of soil contamination in the environment. To prevent the leaching of pollutants in soils, differentstabilization and containment techniques have beendeveloped in recent years. Organophilic bentonites, due to their large surface areas, negative charges on their particles, and highadsorption characteristics have many applications for remediation of contaminated sites. The above characteristics of modified bentonites have enabledthem to adsorb contaminants from solutions or to stabilize them in soils. This study focuses on interlayer changes ofbentonite clays due to the adsorption of hydrocarbons (i.e, Crude Oil, MTBE, BTEX compounds and Gasoline). Free swell tests and Xraydiffraction analysis were conducted on the clays. The free swell test results showed that modified bentonites effectively intercalated crude oil into their particles and adsorb them, hence presenting 410 % volume increase when exposed to this compound. Results of X-ray diffraction analysis for modifiedbentonite samples indicated a 63.15% interlayer increase after their exposure to the crude oil while that of ordinary bentonites was relativelyinsignificant (0.50%). Similar observations were noted for other hydrocarbonic compounds, denoting the organophilic properties of modified bentonites.

Keywords:

Modified clay , Xrd analysis , Free swell test , BTEX compounds , MTBE , Crude oil , Gasoline