Effective Remediation of Oil‐Contaminated Soil Using Synthetic Surfactant–Polymer–Alkali Mixtures

ABSTRACT

Soil contamination by oil is a common environmental issue that poses a potential risk to soil ecosystems, and its remediation remains a challenging task. In this work, two propoxylated sulfonamide derivatives of sodium dodecylbenzene sulfonate (SDBS), viz. Surfactant Type ‐I (ST‐I) and Surfactant Type‐II (ST‐II), were synthesized and characterized by Fourier‐transform infrared (FTIR) spectroscopy. The experimental parameters and their values for SDBS (0.075 wt.%), synthesized surfactants (ST‐I:0.299 wt.%, and ST‐II: 0.506 wt.%), alkali (NaOH: 0.75 wt.%) and polymer (Guar Gum: 2500 ppm) were evaluated through interfacial tension (IFT) and rheological measurements, and activation energy determination. The effectiveness of synthesized surfactant–polymer–alkali (SPA) mixtures in remediating oil‐contaminated soil was analysed through core flooding experiments with the optimum surfactant‐to‐polymer ratio for SDBS (0.8:1), ST‐I (0.6:1) and ST‐II (0.5:1) in 0.75% NaOH solution. The results showed that the optimized ST‐II formulation exhibited the maximum oil recovery of 78.1% of the original oil in place (OOIP) compared to 72.58% for ST‐I and 66.11% for SDBS, whereas conventional waterflooding achieved 49.0% OOIP. Additionally, the Germination Index (GI) was evaluated to assess the phytotoxicity of the contaminated soil, which reinforces the efficacy of the soil remediation process.