(183c) Emulsions of Oil in Seawater Stabilized with Particles and Surfactants

Dispersant systems for oceanic oil spill remediation have gained renewed attention following the Deepwater Horizon oil spill in 2010.  The combination of surfactants and silica or clay nanoparticles and microparticles can provide synergy in the formation and stabilization of dodecane droplets in synthetic seawater. The surfactants lower the oil/water interfacial tension and allows the formation of oil/water emulsions composed of small oil drops (<100 micron diameter), while the presence of nanoparticles at the oil/water interface enhances emulsion stability by providing a larger steric barrier to droplet coalescence than surfactants alone.  The use of particles may therefore reduce the concentration of surfactants required for the dispersion of oil in seawater.

Droplet sizes were analyzed with optical microscopy and static light scattering, and the dispersion mechanisms for various formulations were explored via a small-scale jet apparatus. The generation of droplets via jet breakup is interpreted in terms of energy dissipation, Ohnesorge number, Weber number and Reynolds number. Droplet size and emulsion stability were characterized for a range of dispersant-to-oil ratios as well as oil-to-water ratios.