Adsorption of the tallow amine ethoxylate surfactant Ethomeen T/15 on montmorillonite

Abstract The use of biocompatible surfactants is interesting to increase the properties of clay minerals in an environment-friendly process of charge capacity of organics. The adsorption of the surfactant Ethomeen T/15 in the interlayer space of montmorillonite was studied experimentally and computationally. Different proportions of surfactant, water and phyllosilicate were explored. Calculations at molecular level were performed using forcefields based on empirical interatomic potentials. The surfactant is likely to be adsorbed within the montmorillonite interlayer space forming hydrogen bonds between the H atoms of surfactant and the basal tetrahedral O atoms of the montmorillonite interlayer surface. These hydrogen bonds and the electrostatic interactions between cations and phyllosilicate surface are the main driving forces of the adsorption. Molecular dynamics simulations have indicated several possible conformations of the surfactant molecules in the interlayer space. The combination of molecular modeling, thermal analysis, Fourier transformed infrared spectroscopy (FT-IR) and X-ray diffraction (XRD) has allowed the interpretation of this adsorption process.