Dynamic properties of fine-grained soils engineered with a controlled organic phase

Review of the fundamental geochemical and physical behaviors of organoclays in barrier applications

“…Eq. (11) suggests that organic coating reduced the interaction of the clay mineral with the interlayer water, which agrees with other experimental evidences such as decreased specific surface area and decreased magnitude of zeta potential values (less negative) with increased TOC (Bate and Burns, 2010;Bate et al, 2013).…”

“…Consequently, all cationic surfactants are expected to cover some/all of the mineral surface and decrease the apparent surface area of the surfactant/clay hybrid. Besides, cationic surfactant head groups reduce the inter-particle repulsive forces, can cause particles to aggregate, and therefore can also reduce the surface area (Soule and Burns, 2001;Bate et al, 2013). The study by He et al (2006a) indicated that both the BET-N 2 surface area (b10 m 2 /g for HDTMA clay, compared with 55 m 2 /g for Na-MMT) and pore volume of the organoclays decreased as the long chain surfactant loading increased.…”

“…However, these parameters of organoclays are very limited (Bate, 2011; Bate et al, 2013). Bate et al (2013) and Choo et al (2015) synthesized organoclays by coating montmorillonite with quaternary ammonium cations with different structures and loading densities, and reported the following general trends: (1). G max of organoclays increased with an increase in total organic carbon content (TOC) (via an increase in the size of the organic cations, the length of a single long carbon chain, or the amount of organic loading) (Fig.…”

“…studies on organoclays are limited. A recent study on organobentonites presented that thermal conductivity decreased with increased organic content (Bate, 2011). An increase in the branch size or chain length of the quarternary ammounium cations resulted in a decrease in the thermal conductivity indicating insulation effect of the organic coating (Bate, 2011).…”

Engineering applications of organic surfactant modified bentonite in sorptive soil barriers.

“…It was concluded that small dosage oforganoclayhave a low impact on the overall hydraulic conductivity of soil admixtures when used as additives (Bate 2010;). However, our results suggested that the permeability of compacted silty clay and only 10% of organobentonite to gasoline was decrease by half.For the unsaturated flow in the same compacted soil admixture, the permeability could be even lower for the low-polarity fluids.…”