Treatment of oil-in-saltwater emulsions by in-situ production of magnetic FeOx nanoparticles
By Waller, Gordon H.; Martin, Curtis A.; Jones, Nicholas J.; Paynter, Danielle M.
Published in Journal of Water Process Engineering
2019
Abstract
Oil-in-saltwater emulsions produced to simulate contaminated bilge water were successfully treated by electrochemical oxidation of iron anodes (electrocoagulation). Turbidity measurements of the as-prepared emulsions before and after treatment show a reduction in turbidity of over 98%, while application of a permanent magnet was found to be effective in reducing the settling time for the Fe-oxide containing sludge. Solution temperature was found to be the most critical parameter for influencing the efficiency of the electrocoagulation process, while electrode separation and solution contents (i.e. the presence of surfactants and oil) had less of an influence, especially for a solution temperature of 45 °C. Characterization of the Fe-oxide precipitates by electron microscopy, x-ray diffraction, and vibrating sample magnetometry confirmed that the products were nano-sized crystallites assignable to either Fe3O4 or γ-Fe2O3. All measurements indicated that a secondary phase was present which appeared as a varied particle morphology, a weak diffraction peak in some samples, and a reduced magnetic saturation. These results indicate that further optimization of the electrocoagulation process may be possible which could further improve the magnetic response of the Fe-oxide containing sludge.