Oil Spill Remediation Using Magnetic Separation

Abstract

Magnetic separation technology was applied to remove dispersants and crude oil from water with magnetite and maghemite. Maghemite exhibited rather constant removal efficiency for dispersants regardless of surfactant types, while magnetite exhibited higher removal efficiency for anionic surfactant, and the efficiency was higher in deionized water than in salty water that contains more ions. Sorption of the dispersants to magnetite can be explained with electrostatic attraction, while binding of the dispersants to maghemite can be described with electrostatic attraction as well as with the structural characteristics that provide high sorption capacity. The result from a water bath experiment, which was to test the collection efficiency of magnetic particles from water, indicated that the recovery efficiency of magnetic particles was nearly 100% after the dispersants had been sorbed. More than 80% of the oil was collected when the magnetite-to-oil ratio was more than 0.89, while the same percentage of oil was harvested when the maghemite-to-oil ratio was more than 0.46 in the oil removal experiment. Sorption of crude oil to magnetic particles can be explained with the fine particle–oil flocculation, which is associated with an electrostatic attraction between the magnetic particles with charged surface and polar compounds in the crude oil.