LAUSR

Abstract The remediation of hydrocarbon contaminated soils is an active research field, in which different remediation technological approaches are currently under evaluation. In this research, a new technology based on a self-assembly biopolymer/β-Cyclodextrin/surfactant (bP/βCD/S) CO2 foam system was evaluated for in-situ soil remediation applications. The biopolymer and surfactant used in this study were xanthan gum and dodecyl trimethylammonium chloride (DTAC), respectively. The stability of the bP/βCD/S and the baseline biopolymer/surfactant, bP/S, CO2 foam systems at different brine salinity and hardness concentrations was evaluated in bulk. Subsequently, the flow behavior and the stability of both foam systems were evaluated through displacement experiments employing unconsolidated sand at different brine concentrations (2.1 and 8.4 wt%) at ambient temperature. The mobility control performance and the stability of both foam systems in contaminant-free sand were evaluated during the displacing experiments using the resistance and the residual resistance factors as performance indicators. The bulk stability tests demonstrate that the bP/βCD/S CO2 foam system displays higher stability relative to the bP/S foam system in both 2.1 wt% (e.g., salinity = 1.73 wt% and hardness = 0.37 wt%) and 8.4 wt% (e.g., salinity = 6.92 wt% and hardness = 1.48 wt%) brine systems. Likewise, the displacement experiments show that the bP/βCD/S CO2 system offers superior mobility control functionality and stability during flow in porous media relative to the baseline polymer/surfactant foam regardless of the brine ionic strength. Consequently, the bP/βCD/S CO2 foam system shows great potential as an effective integrated technology for in-situ soil remediation applications.