Use of Lecithin-Based Emulsion Gels to Absorb Toluene and Hexane Spills from Surface Waters

Abstract

Natural sorbents for the removal of free toluene, hexane, and toluene/hexane mixtures from surface water were made using lecithin, food grade oils (canola, sunflower, safflower and corn oil) and water, or lecithin, hydroxystearic acid (HSA) and soy wax. These emulsions were gel-like, with shear elastic moduli (G’) greater than the shear viscous moduli (G”). The addition of either toluene and hexane rigidified lecithin-based gels by altering the structure of the droplet clusters or characteristics of the lecithin films at the oil-water interface. Lecithin based gels could absorb up to 33% of toluene and 67% of hexane over 20 hrs. The addition of HSA and soy wax also increased the cohesiveness of the gels.