Ja. Smith et Pr. Jaffe, BENZENE TRANSPORT THROUGH LANDFILL LINERS CONTAINING ORGANOPHILIC BENTONITE, Journal of environmental engineering, 120(6), 1994, pp. 1559-1577
The mineral surface of Wyoming bentonite was modified by replacing ino
rganic ions by different quaternary ammonium compounds of known molecu
lar structure by an ion-exchange process. The resulting organically mo
dified bentonites (organobentonites) were evaluated for their suitabil
ity as components of compacted earthen liners for waste-disposal sites
. Varying weight percentages of an Ottawa sand, either of five types o
f organobentonites, untreated bentonite, and water were mixed uniforml
y and compacted to simulate sand-and-bentonite liners for waste-dispos
al facilities. The hydraulic conductivities of the compacted soil spec
imens were measured in triplicate. The hydraulic conductivities of com
pacted specimens composed of 88% (by mass) Ottawa sand, 8% untreated b
entonite, and 4% organobentonite were on the order of 10(-8) cm/s. Ben
zene sorption from water to Ottawa sand, bentonite, and two of the org
anobentonites was measured experimentally. Benzene sorption to each or
ganobentonite was significantly greater than benzene sorption to bento
nite or Ottawa sand. The sorption and permeability data were input int
o a one-dimensional solute transport model to simulate benzene transpo
rt through a conventional earthen liner and two liners containing orga
no-bentonites. Results of the simulations indicate that earthen liners
containing organobentonites significantly retard the transport of ben
zene relative to a conventional liner.