Influence of CTAB-Grafted Faujasite Nanoparticles on the Dynamic Interfacial Tension of Oil/Water Systems

In this study, the dynamic IFT and dilational rheological behavior of fluids/nanofluids generated from cetylbased nanoparticles were investigated in toluene-fluid/nanofluid interfaces under various conditions. To generate each nanofluid, FAU nanoparticles were initially synthesized under ambient conditions and then grafted with various quantities of CTAB surfactants. Afterward, the surface properties (i.e., morphology, surface area, functionality, and stability) of the synthesized nanoparticles before and after grafting with a low concentration of CTAB molecules were investigated by an array of characterand DLS). The results showed that our generated FAU-based nanofluids outperformed the nongrafted FAU and physically mixed CTAB with FAU-based nanofluids in terms of IFT reduction. Our experimental IFT data were fitted with a general diffusion model that allowed us to determine the oil-water (o/w) emulsification mechanism due to the presence of CTAB-grafted nanoparticles. Based on our investigation, we emphasized that the IFT reduction was limited with the loading of a substantial amount of surfactant molecules, indicating that bulky nanoparticles are adsorbed slowly on the o/w interface. On the other hand, increasing the salinity level by introducing an additional amount of NaCl led to enhancing the levels of IFT reduction since the dissociated ions forced more surfactant molecules to migrate toward the o/w interface. A considerable viscoelasticity enhancement was remarked in the presence of our CTAB-grafted nanofluids, indicating that the presence of FAU nanoparticles in the core of the grafted nanoparticles robustly allowed the adsorption of higher amounts of CTAB molecules at the interface with less aggregation. The findings of this study shed light on the applications of nanofluids generated from grafted nanoparticles at the o/w systems, which can significantly increase the oil production at the end of water flooding with more efficient emulsification with surfactant concentration lower than the critical micelle concentration (CMC).