Study on the Removal Efficiency of Sodium Dodecylbenzene Sulfonate Compound System for Aniline in Soil

Taking the soil samples from a contaminated site in an industrial park in northwest China as the research object, through one-dimensional simulated column leaching experiments and orthogonal tests, this study explored the influences of surfactant concentration, pH value, n-propanol concentration, and NaCl concentration in the sodium dodecylbenzene sulfonate (SDBS) compound system on the removal efficiency of aniline in contaminated soil. The order of the effects of the factors on the removal efficiency of aniline was determined, and the interaction among the factors was analyzed. The results indicate that the order of the effects of the factors on the removal efficiency of aniline was as follows: SDBS concentration > pH value > NaCl concentration > n-propanol concentration. There were significant interactions between SDBS concentration and pH, and between NaCl concentration and n-propanol concentration. Under the optimal conditions, i.e. SDBS concentration of 8 times the critical micelle concentration (CMC, 650 mg·L^-1), pH 10, n-propanol 8 000 mg·L^-1, NaCl 4 000 mg·L^-1, the removal rate of aniline reached 92.86%, which was 18 percentage point higher than that of pure water leaching. This study reveals the synergistic mechanism of SDBS micelle solubilization, n-propanol competitive adsorption, and NaCl regulation of micelle stability, confirming that the compound system significantly enhanced the removal of pollutants through multiple effects. This achievement provides a theoretical basis and technical support for the remediation of aniline-contaminated soil.