Application of Modified Clays in Geosynthetic Clay Liners for Containment of Petroleum Contaminated Sites

Document Type : Original Research Paper


1 Faculty of Environment, University of Tehran, P.O.Box 14155-6139, Tehran, Iran

2 Faculty of Engineering, Kharazmi University, Tehran, Iran


In this research, hydraulic and sorption behavior of geosynthetic clay liners (GCLs) with
ordinary and modified clay exposed to crude oil were studied. Both modified and ordinary bentonites were
investigated to evaluate crude oil adsorption efficiency on the liners. Because soil permeability exposed to
crude oil is a major parameter in measuring the contaminants migration in soils, the permeability tests were
conducted on the clays. X-ray diffraction (XRD) analyses were also carried out to evaluate the adsorption of
crude oil by bentonites. Following the tests, results of XRD analysis for modified bentonite samples indicated
an average 63.2% interlayer increase after their exposure to the crude oil while that of ordinary bentonite was
relatively insignificant (0.5 %). In case of permeability tests, modified bentonites showed much lower
permeability values (5.2 × 10-9 cm/s) compared to ordinary bentonites (1.2 × 10-6 cm/s) when exposed to
crude oil, hence denoting the viability of modified clays, instead of ordinary clays as GCLs materials at
petroleum contaminated sites.