Parameters Governing the Adsorption of Crude and Bunker Fuel Oils to Seawater Suspended Particulate Matter

Abstract

In this study, parameters influencing the adsorption of dispersed oil droplets to suspended particulate matter (SPM) in seawater were investigated. The interaction between oil and SPMs can alter the ultimate fate of oil spilled in marine environments, and it is therefore of interest to be able to predict the effect of these interactions. The chosen parameters of this study were sediment type (carbonate sand, quartz sand and clay) and concentration (5-80 g/L seawater), temperature (5-20 °C) and oil type (two crudes, one condensate and a heavy fuel oil). Special attention was given to the effect of adding chemical dispersant to the oil prior to mixing with water and SPMs.The experimental outline included the mechanical generation of oil droplets using an oil droplet generator. Water with oil droplets were added to a beaker with sediment and a suspension was induced by stirring. After settling and filtration, both the water samples and the sediment samples were subject to extraction, clean-up and analysis by GC-FID. A selection of samples was also analysed by GC-MS.The study shows that oil droplets adsorb as a bulk to SPM. An absence of water-soluble oil components adsorbed to the sediment was observed. Oil type, sediment size and the use of chemical dispersant stand out as most influencing on the adsorption properties of oil droplets to SPM in seawater. The effect of varying temperature was not considerable compared to the other parameters in this study. Partitioning of oil components to the water column was also monitored in this study, and found not to be influenced significantly by any of the studied parameters.