Incorporation of clay nano-particles in aqueous foams

During the process of crude oil/gasoline loading and storage, significant amounts of volatile organic compounds (VOCs) can be emitted to the environment. Stable aqueous foams can be spread as a flexible blanket on the top of the oil to control the VOC emission by providing a mass transfer barrier during the loading process. In this work, novel aqueous foams have been formulated by incorporating clay nanoparticles in an aqueous solution of surfactants and polymers. The stability and mass transfer resistance of these foams were investigated at temperatures up to 125 F. In the presence of VOC, clay decreases the rate at which the liquid is drained out of the foam lamellae and increases the foam drainage half-life. These foams were found to be very stable in the presence of gasoline and crude oil and can last much longer than one day at the room temperature. The use of clay in the foam formulation reduces vapor diffusion through the lamellae and vapor emission through the foam column significantly for the first 10 h. Increase in temperature increases the rate of foam breakage due to higher water evaporation and lower liquid viscosity. In spite of this increase, the 0.5% polymer and 0.5% clay foam suppresses vapor emission from a gasoline longer than 3600, 1500 and 1100 min at 75 F, 105 F and 125 F. respectively. This foam also suppresses vapor emission from a crude oil longer than 4200, 2000 and 700 min at 75 F, 105 F and 125 F, respectively. (C) 2009 Elsevier B.V. All rights reserved.