Interaction of Cationic Surfactants with Iron and Sodium Montmorillonite Suspensions

Preparation of organovermiculites using HDTMA: Structure and sorptive properties using naphthalene

“…The cation exchange proceeds more easily, when the interlayer gallery is filled partly and organic cation penetrations become more complicated with increasing packing density. In this study, results are in accordance with HDTMA sorption isotherms on clays (smectites) [1,8,9,[14][15][16][17][18][19][20][21][22]. The sorption isotherm is described with Langmuir equation.…”

Electrochemical permeability measurements of hydrophilic and hydrophobized montmorillonite films

“…The effect of anions is negligible, since the large concentration of NaCl neutralizes the effect of Br − counter ions. This also counts for another phenomenon: CMC values in the case of DTAB and CTAB are significantly smaller in the presence of the electrolyte than in an aqueous solution without it (DTAB: 1.6×10 −2 mol dm −3 and CTAB: 0.9×10 −3 mol dm −3 with no electrolyte [45]; while in 0.01 mol dm −3 KBr at 25 • C, for DTAB: 9.3 × 10 −3 mol dm −3 and for CTAB: 0.8 × 10 −3 mol dm −3 [50]). CMC values (measured of the surface tension with the DuNouy ring method) were not feasible for Gemini surfactants due to their poor water solubility and the effect of NaCl.…”

“…Non-associated, individual molecules intercalate in the case of the former, while as for the latter, solutions at higher than CMC will result in micelle intercalation-occurring parallel to ionic exchange adsorption-onto and into the montmorillonite film [2][3][4][5][6]. In detail, at c > CMC there is micelle formation in the solution, hemimicelle formation on the outer surface of clay particles, and surfactant bilayer formation between TOT layers inside the particles [40][41][42][43][44][45]. These processes are altered by the type of the clay, the length of the surfactant's Table 1 Critical micelle concentrations of some cationic surfactants in 0.1 mol dm −3 NaCl solutions (25 • C)…”

Preparation and characterization of novel clay/PLA nanocomposites

“…The characteristics of surfactant absorption are complex and multi-faceted (Theng et al, 1967;Lagaly and Weiss, 1971;Pan et al, 1997;Chen et al, 1998). The orientation of the adsorbed alkylammonium is a function of the layer composition and charge density of the clay (Lagaly and Weiss, 1971;Ertem et al, 2010), and these aspects tend to differ amongst bentonitic montmorillonites (Jonas and Roberson, 1966).…”