Evaluation of stability and performance of foam composed of complex mixtures of surfactant, nanoparticles and polymer for in-situ remediation of LNAPL
Résumé
Light Non-Aqueous Phase Liquids (LNAPL: gasoline, diesel, motor oil, etc.) - immiscible organic liquids which are one the most common source of groundwater pollution, particularly in France they represent 37.22% of polluted sites. The presence of LNAPL in subsurface mostly associated with
accidental spills and leaks during storage and transportation. As a result of the low mass removal efficiency of the pump and treat in-situ environmental remediation (ER) methods are receiving more attention thanks to the lower risk of contaminant migration and higher sustainability. Moreover, due to the heterogeneity of the soil, even the more advanced recovery methods like in-situ surfactant flushing reach their technical limits. Injected fluid preferentially flows in highly permeable areas caused by differences in viscosity.
Among the increasing interest in shear-thinning fluids for in-situ ER, foam (being 60-99% of gas in a continuous liquid phase) is a promising displacing agent. However, it is worth noting the main challenge of using foam for ER. When foam gets in contact with organic compounds, its stability deteriorates dramatically, which leads to poor sweeping efficiency. A current focus among many foam stability studies is on methods to enhance foam using a variety of additives, such as co-surfactants, polymers, and nanoparticles (NPs). It should be noted that the majority of these studies are focused on foam applications in EOR. Thus, our study focuses on (i) determining the destructive effect of LNPL on foam properties, (ii) examining the stability of foam generated by two or more additives in the presence of a contaminant, both in bulk form and in porous medium, (iii) evaluating the recovery yields of each of the foaming formulations.
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