Solubilization of polycyclic aromatic hydrocarbons by anionic–nonionic mixed surfactant
ABSTRACT Surfactant-enhanced remediation (SER) is an effective approach for the removal of sorbed hydrophobic organic compounds (HOCs) from contaminated soils. The solubilization of polycyclic aromatic hydrocarbons (PAHs) by an anionic–nonionic mixed surfactant, sodium dodecyl sulfate (SDS) with Triton X-405 (TX405), was studied from measurements of the maximum additive concentration (MAC), the micelle–water partition coefficient (Kmc) and the critical micelle concentration (CMC). The results are also compared with that predicted by the ideal mixing rule. The MAC and Kmc values for each PAHs in mixed surfactant are found to be larger than those calculated according to the ideal mixing rule. The mixing effect on MAC and Kmc values for PAHs follow the order of pyrene > phenanthrene > acenaphthene > naphthalene and increase with an increase in the octanol–water partition coefficient (Kow) of PAHs. The CMCs of mixed surfactant show a greater negative deviation from ideal mixture and the SDS–TX405 mixed system has a synergism in the mixed micelle formation. The conjunct role of mixing effect on Kmc and CMC results in the positive deviation of PAHs experimental MACs from the ideal mixture. The correlation of MAC with Kmc and CMC can be utilized as an effective tool to predict the solubilization capability of HOCs by anionic–nonionic mixed surfactants.
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ABSTRACT: Aiming to reduce herbicide leaching, "in situ" adsorption of herbicide-micelle formulations to soils was explored. Sulfentrazone or metolachlor were solubilized in cationic micelles and these herbicide-micelle formulations were applied to sandy and alluvial soils. Sulfentrazone adsorption to the soils was negligible; however, its adsorption via its solubilization in micelles and their adsorption to the soil, was significant and in good agreement with the Freundlich and Langmuir models. Adsorption of solubilized herbicide to the sandy soil was higher than to the alluvial soil. The low ratio between the surfactant concentration and the cation exchange capacity (CEC) of the alluvial soil brought upon micelle decomposition and reduction in herbicide adsorption. Therefore, an optimized ratio between surfactant and soil CEC was chosen to maximize herbicide retention. Even upon adding relatively low loadings of surfactant (0.075-0.3% w/w soil) herbicide leaching through the soils was significantly reduced (2-5 fold) in comparison with the commercial formulations.Journal of Agricultural and Food Chemistry 12/2013; · 2.91 Impact Factor
- Biophysical Journal 01/2011; 100(3). · 3.67 Impact Factor
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ABSTRACT: This study describes the biodegradation of phenanthrene in aqueous media in the presence and in the absence of a surfactant, Brij 30. Biodegradations were performed using either Pseudomonas putida DSMZ 8368 or a bacterial consortium Pyr01 isolated from one PAHs-polluted site. P. putida degraded phenanthrene to form 1-hydroxy-2-naphthoic acid (1H2Na) as the major metabolite. LC-MS analysis revealed the production of complementary intermediates in the presence of Brij 30, showing intense ions at mass-to-charge ratios (m/z) 97 and 195. Higher phenanthrene biodegradation rate was obtained in the presence of Brij 30. Conversely, in the case of Pyr01consortium, the addition of Brij 30 (0.5 g L(-1)) had a negative effect on biodegradation: no phenanthrene biodegradation products were detected in the medium, whereas a production of several intermediates (m/z 97, 195 and 293) was obtained without surfactant. New results on phenanthrene metabolism by P. putida DSMZ 8368 and Pyr01 consortium in the presence and in the absence of Brij 30 we obtained. They confirm that the knowledge of the effect of a surfactant on bacterial cultures is crucial for the optimization of surfactant-enhanced PAHs biodegradation.Indian Journal of Microbiology 09/2012; 52(3):420-6. · 0.46 Impact Factor