Impact of Iron oxide Nanoparticles on aqueous firefighting foam stability

Although aqueous foam has been widely used in firefighting industry, its instability is still a problem during its applications. Study on aqueous foam properties is the key to improving the utilisation efficiency of foam products. In the last years, mixtures of nanoparticles with aqueous foams have been widely used to improve their stability and increase their potential in firefighting purposes. Influence of iron oxide nanoparticles on the aggregation behaviour, foam drainage and foam coarsening of a commercial firefighting foam was systematically studied. The results indicate that the addition of iron oxide nanoparticles increase the foam drainage time, thus increasing the stability of the foam to withstand longer time to collapse. In addition, superficial morphology images demonstrate that the nanoparticles reduce bubble coarsening over time by aggregation of the nanoparticles on the surface of the foam. This study suggests that iron oxide nanoparticles could improve the stability of aqueous conventional foams with addition of appropriate concentrations and expedite the development of a long-term stable foam with potential application in firefighting purposes.