Capture and Densification of Floating Hydrophobic Liquids by Natural Granular Materials

摘要

Densification and submergence of floating crude oil is proposed as a novel oil spills treatment method. Surface application of dry granular materials (e.g., quartz sand, limestone) on top of a floating oil layer increases the density of the floating oil phase/granule mixture and leads to formation of relatively large and stable aggregates with significant amounts of captured oil. The aggregates separate from the floating hydrophobic phase and settle by gravity. Implementation of this method will reduce the impact radius of a spill and its mobility, preventing direct contamination of beaches, coastal flora and fauna.;The major objective of this research was to examine interactions of particles with hydrophobic liquid-water interface from different perspectives. The important characteristics of the process, such as oil removal efficiencies, optimal particle-to-oil ratios and particle size ranges, were experimentally defined. A series of experiments was conducted to investigate aggregation and dissolution rate constants of the submerged hydrophobic liquids in salt water and deionized water, and to study the impact of the surface porosity of the granular particles on oil capture efficiencies. In addition to crude oil (South Louisiana crude, MC 252), aggregation volumes of quartz sand with other hydrophobic liquids (alkanes and aromatics) were analyzed in relation to wetting characteristics and physical properties of the liquids. A classification of the main types of oil-particle aggregates was developed based on the formation characteristics of the aggregates. Moreover, under specific conditions, depending on the application rates of the granular materials, unique interactions of the particles with the hydrophobic liquid-water interface were observed and defined (bowl formation and roping).;These concepts can be utilized to control surface mobility of floating oils, especially during the initial stages of an oil spill, while the oil layer is intact, and when other treatment methods may not be suitable near coastal areas, where transport of floating oils can significantly impact coastal ecosystems.