application of modified clays in geosynthetic clay liners for containment of petroleum contaminated sites

in this research, hydraulic and sorption behavior of geosynthetic clay liners (gcls) withordinary and modified clay exposed to crude oil were studied. both modified and ordinary bentonites wereinvestigated to evaluate crude oil adsorption efficiency on the liners. because soil permeability exposed tocrude oil is a major parameter in measuring the contaminants migration in soils, the permeability tests wereconducted on the clays. x-ray diffraction (xrd) analyses were also carried out to evaluate the adsorption ofcrude oil by bentonites. following the tests, results of xrd analysis for modified bentonite samples indicatedan average 63.2% interlayer increase after their exposure to the crude oil while that of ordinary bentonite wasrelatively insignificant (0.5 %). in case of permeability tests, modified bentonites showed much lowerpermeability values (5.2 × 10-9 cm/s) compared to ordinary bentonites (1.2 × 10-6 cm/s) when exposed tocrude oil, hence denoting the viability of modified clays, instead of ordinary clays as gcls materials atpetroleum contaminated sites.