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Effect of nonionic surfactants on naphthalene dissolution and biodegradation
H Mulder1, G R Wassink, A M Breure
1Laboratory for Ecotoxicology, National Institute of Public Health and the Environment, P.O. Box 1, 3720 BA Bilthoven, The Netherlands. eric.mulder@rivm.nl
Biotechnology and Bioengineering
|April 1, 1999
Summary
This study shows that nonionic surfactants increase naphthalene dissolution rates by enhancing mass transfer. Surfactant concentration and micelle properties significantly impact dissolution and subsequent biodegradation by Pseudomonas bacteria.
Area of Science:
- Environmental chemistry
- Bioremediation
- Chemical engineering
Background:
- Naphthalene is a common environmental pollutant.
- Surfactants can enhance the dissolution of hydrophobic organic compounds.
- Understanding surfactant effects is crucial for bioremediation strategies.
Purpose of the Study:
- To investigate the impact of six nonionic surfactants on naphthalene dissolution rates.
- To evaluate the influence of surfactant concentration and micelle properties on mass transfer.
- To examine the combined effects of dissolution and biodegradation.
Main Methods:
- Stirred batch reactor experiments were used to measure dissolution rates.
- A mechanistic mass-transfer model was employed to describe the dissolution process.
- Combined dissolution and biodegradation experiments were conducted with specific surfactants and naphthalene-degrading bacteria.
Main Results:
- Increased surfactant concentrations up to 10 kg m-3 enhanced naphthalene mass-transfer rates.
- Naphthalene partitioning into micelles and micelle diffusion coefficients were key factors.
- Biomass formation rate of Pseudomonas 8909N increased with mass-transfer rates up to 6 kg m-3 surfactant concentration.
Conclusions:
- Nonionic surfactants significantly enhance naphthalene dissolution.
- Mass-transfer modeling accurately describes the observed dissolution behavior.
- Surfactant-enhanced dissolution can improve the efficiency of naphthalene biodegradation.