Synergistic effects of AlOOH and sodium benzenesulfonate on the generation of Pickering emulsions and their application for enhanced oil recovery

The surfactant assisted nanoparticle stabilized emulsions exhibit the wide potential application and attract more and more attention. In the present study, the flake-like hydrophilic AlOOH nanoparticles were employed to stabilize Pickering emulsions with the assist of slightly amphiphilic sodium benzenesulfonate (SBS) molecules. The measurements of FTIR spectra, three-phase contact angle, zeta potential and Z-average diameter adequately testified the successful adsorption of SBS on AlOOH nanoparticles. Both slightly amphiphilic SBS and highly hydrophilic AlOOH nanoparticles could hardly stabilize emulsions, whereas the SBS modified AlOOH nanoparticles exhibited distinguished emulsifying capacity, which was reflected via the Turbiscan Stability Index and the reference values of backscattered light intensity. Batch adsorption experiments were conducted and the adsorption data was better fitted to the Langmuir model, suggesting that SBS could form monolayer adsorption on AlOOH nanoparticles. Confocal laser scanning microscopy and rheological measurements demonstrated that the functionalized AlOOH nanoparticles could spontaneously adsorb at the oil/water interface to form an interfacial film and generate a three-dimensional network structure in the continuous phase to effectively prevent droplet coalescence in normal and harsh conditions. Furthermore, SBS/AlOOH stabilized O/W emulsions presented significant displacement performance (tertiary oil recovery of 18.87%) in core flooding experiments. Microscopic visualization tests showed that the emulsions could block high permeability channels and enlarge the sweep area. This study opens up the possibility of adopting low surface-active molecules and hydrophilic nanoparticles to stabilize Pickering emulsions for enhanced oil recovery (EOR).