Effect of total organic carbon content and structure on the electrokinetic behavior of organoclay suspensions

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

“…As a result, the long-term performance of hydraulic conductivity often increases and swelling potential decreases for a GCL barrier system (Scalia and Benson, 2010). However, in organic surfactant modified clays, other driving forces for the adsorption of organic compounds and surfactants onto solid surfaces such as covalent bonding, hydrogen bonding, hydrophobic lateral interaction, solvation and desolvation may prevail in addition to the Coulombic forces (Bate and Burns, 2010). As a result, the affinity of quaternary ammonium cations (QACs) with long carbon chain to the clay surface is significantly higher than Na ions (Bate and Burns, 2010).…”

“…However, in organic surfactant modified clays, other driving forces for the adsorption of organic compounds and surfactants onto solid surfaces such as covalent bonding, hydrogen bonding, hydrophobic lateral interaction, solvation and desolvation may prevail in addition to the Coulombic forces (Bate and Burns, 2010). As a result, the affinity of quaternary ammonium cations (QACs) with long carbon chain to the clay surface is significantly higher than Na ions (Bate and Burns, 2010). Consequently, the adsorption of polymers on solid surfaces is often irreversible due to the accumulative bonding energy from many segments on the chain (Stumm and Morgan, 1996).…”

“…Net surface charge governs Columbic repulsive and attractive forces between particles (and therefore governs swelling potential), and dictates the fabric patterns and aggregations of clay particles (and therefore dictates soil density and hydraulic conductivity). However, except for limited use of zeta potential on laboratory testing of barrier materials (Bate and Burns, 2010), zeta potential is rarely used in the field barrier system. This could be due to the limited availability in both device and expertise, especially in the field.…”

“…Comparing to that of an unmodified Na-bentonite, ζ of orgnaoclays often increases with total organic content because of the high affinity of quaternary ammonium cations, especially those with long carbon chains whose adsorption is essentially irreversible (Bate and Burns, 2010). Zeta potential of organoclays in a barrier system permeated with organic or inorganic fluids, however, has rarely been reported.…”

Microstructure of different chain length ionic liquids intercalated into montmorillonite: A molecular dynamics study

“…Most commonly, Na-montmorillonite is used as the base mineral clay and its sodium cations can be exchanged with quaternary ammonium cations (Burns et al, 2006;Soule and Burns, 2001). QAC-coated montmorillonite exhibits higher zeta potential (Bate and Burns, 2010), enhanced strength, lower compressibility, and stronger retention of organic compounds (Lo, 2001;Redding et al, 2002) in the environment, yielding a variety of potential applications in waste containment, landfill liners, and slurry walls (Lorenzetti et al, 2005;Park and Jaffe, 1993;Sheng and Boyd, 1998;Smith and Jaffe, 1994). The structure of the surfactant (e.g., chain length, number of long chains, head group) and the intrinsic properties of the original clay material have a combined effect on the structure and properties of the resultant organoclay (Bergaya et al, 2006;Ha and Char, 2005;He et al, 2006;Osman et al, 2004;Xi et al, 2005aXi et al, , 2005b.…”