Conditions for effective removal of pyrene from an artificially contaminated soil using Pseudomonas aeruginosa 57SJ rhamnolipids

The efficacy of a new rhamnolipid biosurfactants mixture to enhance the removal of pyrene from a soil artificially contaminated was investigated. The molar solubilization ratio (MSR) and the partition coefficient between the micelles and water (log Km) were found to be 7.5 × 10−3 and 5.7, respectively. From soil column studies, the pyrene removal increased linearly with the concentration of the injected biosurfactants solution above the effective critical micellar concentration (0.4 g L−1). Flushing with a 5.0 g L−1 biosurfactants solution increased the pyrene concentration in the effluent by 178 times. At high biosurfactantsʹ concentrations (2.5 and 5.0 g L−1), the cumulative pyrene recovery reached 70%. This pyrene remobilization takes place independently of the soil organic carbon solubilization. This study provides a combination of batch and column experiments in order to find the conditions for effective soil remediation using a new rhamnolipids mixture. The potential of newly isolated biosurfactants to mobilize PAHs from contaminated soils was evaluated from the determination in dynamic conditions of their effective critical micellar concentration.