Solubilization and biodegradation of phenanthrene in mixed anionic-nonionic surfactant solutions

Area of Science:

• Environmental Chemistry
• Bioremediation
• Surfactant Science

Background:

• Polycyclic aromatic hydrocarbons (PAHs) like phenanthrene pose environmental risks.
• Effective remediation strategies are crucial for contaminated sites.
• Surfactants can enhance the bioavailability and degradation of hydrophobic pollutants.

Purpose of the Study:

• To investigate the impact of mixed anionic-nonionic surfactants on phenanthrene solubility and biodegradation.
• To compare the efficacy of single versus mixed surfactant systems.
• To evaluate the synergistic effects of different surfactant combinations.

Main Methods:

• Investigated mixtures of sodium dodecyl sulfate (SDS) with Tween80 (TW80), Triton X-100 (TX100), and Brij35.
• Measured critical micellar concentrations (CMCs) and phenanthrene solubilization.
• Assessed phenanthrene biodegradation by microorganisms in the presence of surfactants.

Main Results:

• Mixed surfactants exhibited lower CMCs than SDS alone.
• Solubility enhancement followed the order SDS-TW80 > SDS-Brij35 > SDS-TX100.
• SDS-Brij35 showed significant synergistic solubilization of phenanthrene.
• Mixed surfactants did not inhibit, and even promoted, phenanthrene biodegradation within 96 hours.

Conclusions:

• Anionic-nonionic surfactant mixtures effectively enhance phenanthrene solubility and biodegradation.
• Synergistic effects were observed, particularly with SDS-Brij35.
• These findings support the use of mixed surfactants for improved remediation of PAH-contaminated soils.