Biosurfactant-driven desorption and remediation of heavy oil contaminated soils underpinned by molecular simulations and microbial dynamics

TL;DR

This study explores how biosurfactants can help clean oil-contaminated soils by combining simulations and experiments.

Contribution

The study introduces a novel integration of molecular simulations and microbial analysis to optimize biosurfactant-based soil remediation.

Findings

Montmorillonite showed the highest oil adsorption capacity in both simulations and experiments.

Sophorolipid was the most effective biosurfactant for oil desorption from mineral substrates and contaminated soil.

Biosurfactant use increased the abundance of oil-degrading bacteria, enhancing bioremediation.

Abstract

This study integrates molecular dynamics simulations and bench-scale experiments to investigate the adsorption and desorption behaviors of heavy oil on five mineral substrates: SiO2, kaolinite, muscovite, and Ca2+-/Na+-montmorillonite. Adsorption followed Langmuir isotherms, with montmorillonite exhibiting the highest capacities (0.061–0.062 molecules per Å2 for aromatics in simulations; 0.086–0.091 g g−1 in bench-scale tests) and SiO2 the lowest (0.027 pcs per Å2; 0.013 g g−1). Among four biosurfactants evaluated—rhamnolipid, sophorolipid, trehalose lipid, and mannosylerythritol lipid–sophorolipid consistently achieved the greatest desorption efficiency, removing up to 99.63% of adsorbed oil from Na+-montmorillonite and 96.04% from field-contaminated soil. 16S rRNA and metagenomic sequencing revealed an increased abundance of hydrocarbon-degrading bacteria within the soil microbial community, highlighting a synergistic effect between biosurfactant-induced desorption and biodegradation. These findings underscore the critical roles of mineralogical properties, oil fraction characteristics, and biosurfactant selection in soil washing treatment. This work presents a viable and eco-friendly strategy for remediating crude oil-contaminated soils, with important implications for optimizing large-scale environmental restoration efforts.

This study integrates molecular dynamics simulations and bench-scale experiments to investigate the adsorption and desorption behaviors of heavy oil on five mineral substrates: SiO2, kaolinite, muscovite, and Ca2+-/Na+-montmorillonite.

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