Using Flotation to Separate Oil Spill Contaminated Beach Sands

Abstract

Lab flotation in artificial sea water was used to separate sand-oil mixtures prepared by mixing crude oil with quartz-dominated beach sands. Major factors affecting the separation efficiency for three representative oils (light, waxy, and heavy viscous) were examined through lab flotation tests, vortex experiments, and oil viscosity measurements. Results showed that flotation in sea water can effectively separate the tested sand-oil mixtures which had large contrast in physicochemical properties: (1) aging of sand-oil mixtures reduced the separation efficiency; (2) both the viscosity of crude oil and its adhesion to sand surfaces had major impacts on separation efficiency; (3) addition of small amounts of surfactants could substantially improve the separation efficiency; and (4) for heavy viscous oil, hydrocarbon solvents needed to be added to improve separation because of their solvency and capability in reducing oil viscosity.