Influence of ZrO₂ Nanoparticles Including SDS and CTAB Surfactants Assembly on the Interfacial Properties of Liquid-Liquid, Liquid-Air and Liquid-Solid Surface Layers

This work investigates the effects of nanometric (5-8 nm) ZrO₂ nanoparticles on adsorption of two surfactants, SDS (sodium dodecyl sulfate) and C₁₂TAB (dodecyl trimethyl ammonium bromide) into oil/water, air/water and solid/water interfaces. Increasing the concentration of nanoparticles reduces the interfacial tension and surface tension of SDS at low surfactant concentration (< cmc) but it has a minor effect on interfacial and surface tension of C₁₂TAB. Repulsive columbic interactions between SDS molecules and nanoparticles can cause the higher adsorption of surfactant at the oil/water interface. Adsorption of both surfactants on carbonate rock increases by adding nanoparticles to the system. This possibly happened because of the formation of surfactant-nanoparticle negatively charged aggregates that tend to adsorb on positively charged surface layer of carbonate rock. ZrO₂ nanoparticles are surface active at the oil/water interface too, as the results of interfacial tension indicate they can decrease the n-heptane/water IFT about 14 units.