Aggregation of diesel fuel-contaminated kaolin via interfacial behaviors among mineral, water, and pollutant

Understanding the interfacial interactions among minerals, water, and pollutants is critical for elucidating aggregation mechanisms in diesel fuel-contaminated soils. This study investigates kaolin aggregation using molecular dynamics simulations combined with aggregate distribution analysis under varying thermal conditions. The results reveal a significant transition in the dominant factor controlling aggregate distribution, shifting from pollutant concentration to water content with increasing hydration. At low water contents (8% and 18%), increasing temperature induces aggregate dispersion primarily through thinning of water film. In contrast, at 28% hydration, heating promotes aggregate compaction due to the synergistic effects of pollutant migration and water film expansion. Elucidating these contrasting temperature-dependent mechanisms and the associated shift in dominant controlling factors provides valuable insights for optimizing thermal remediation strategies for contaminated soils.