Enhanced soil flushing of phenanthrene by anionic-nonionic mixed surfactant

Area of Science:

• Environmental Science
• Soil Remediation
• Surfactant Chemistry

Background:

• Soil contamination by polycyclic aromatic hydrocarbons like phenanthrene poses environmental risks.
• Surfactant-enhanced soil flushing is a promising remediation technology.
• Optimizing surfactant mixtures is crucial for improving remediation efficiency.

Purpose of the Study:

• To investigate the performance of anionic-nonionic mixed surfactants (SDS and TX100) for phenanthrene flushing from contaminated soil.
• To evaluate the effect of SDS mass fraction on TX100 sorption and phenanthrene solubilization.
• To enhance the efficiency of surfactant remediation technology.

Main Methods:

• Laboratory column experiments were conducted using phenanthrene-contaminated soil.
• Batch experiments were performed to assess surfactant sorption.
• Mixed surfactant solutions of sodium dodecyl sulfate (SDS) and Triton X-100 (TX100) were used.
• Phenanthrene flushing efficiency was measured.

Main Results:

• Sorption of TX100 onto soil was significantly reduced in the presence of SDS.
• Phenanthrene solubilization was enhanced by SDS-TX100 mixed surfactants compared to individual surfactants.
• Flushing efficiencies increased with higher SDS mass fractions in the mixed surfactant solutions.
• Mixed surfactant micelles formation explained the enhanced solubilization.

Conclusions:

• Anionic-nonionic mixed surfactants (SDS-TX100) are effective in enhancing phenanthrene flushing from contaminated soil.
• The presence of SDS inhibits TX100 sorption, leading to improved soil flushing.
• Optimizing the mass fraction of SDS in mixed surfactants can maximize phenanthrene removal efficiency.