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: The overall goal of this study was to improve the solubility of tar compounds in water using a surfactant, sodium dodecyl sulfate (SDS). The solubility experiments were performed using 100-ml media bottles. Benzene, toluene, ethylbenzene, styrene, and p-xylene were used as model tar compounds because these compounds are sparingly soluble in water. The solubility of tar compounds was measured using UV/VIS spectrophotometer. Statistical analysis showed that solubilities of tar compounds improved significantly (p b 0.0001) using SDS above the critical micelle concentration. Experimental results showed that the solubility of benzene, toluene, ethylbenzene, styrene and p-xylene increased 4 to 14, 9 to 33, 19 to 69, 18 to 83 and 29 to 135 fold, respectively, as SDS concen-tration increased from 0, i.e., water as control to 15, 30, 45 and 60 g/L at solvent temperature of 20 °C. Results also showed that solubilities of benzene, toluene and ethylbenzene decreased as the solvent temperature increased.Fuel Processing Technology 01/2015; 133:75–79. DOI:10.1016/j.fuproc.2015.01.008 · 3.02 Impact Factor
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ABSTRACT: Combining technologies offer a great potential to phytoremediate contaminated soils. As sequestration occurs, pollutants availability decline and organic amendments could counterbalance that situation. This work studies the potential of willow plants to phytoremediate soil containing p,p'-DDT (101.3 ng g(-1)) and p,p'-DDE (381.4 ng g(-1)) residues. The effect of root exudates, Tween 80 and citric and oxalic acids on DDTs desorption and availability from soil was tested together with the plant uptake and translocation. Treatments increased the p,p'-DDE/p,p'-DDT ratio when compared with control (water) soil. Watering with carboxylic acids led to a significant enhancement of the quantities of p,p'-DDT and p,p'-DDE desorbed from soil that was related with an increase of organic carbon in solution. Willow plants accumulated DDTs under all treatments although plants watered with carboxylic acids showed the highest leaves translocation factor for both p,p'-DDT and p,p'-DDE. Results indicate that the addition of carboxylic acids enhanced DDTs bioavailability which further increases plant uptake and translocation. The effect of surfactants on the soil-plant systems needs to be better assessed for this particular soil and plant species. The enhancement of soluble organic carbon is crucial at the moment of evaluating DDTs release from soil as well as to establish cleaning strategies.Journal of hazardous materials 12/2011; 203-204:62-8. DOI:10.1016/j.jhazmat.2011.11.080 · 4.33 Impact Factor
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ABSTRACT: Laboratory experiments were carried out to study the effects of cationic surfactant cetyltrimethylammonium chloride (CTAC) on the uptake of pyrene by fish gills. The uptake (including adsorption) of pyrene by gills of the color carp (C. carpio var. color) exposed to 20-100 microg/L pyrene in the presence or absence of 0.2-1.0 mg/L CTAC were determined. The sorption of pyrene by mucus was preliminary studied using a four-step sequential extraction procedure. Fish gills were extracted with H2O, 0.01 M CaCl2, CH3OH and a mixture of 1:1 n-C6H14/CH2Cl2 in sequence. Results showed that pyrene mostly accumulated in mucus and on the surface of gills tissue; the cationic surfactant CTAC significantly enhanced these accumulation or adsorption on the fish gills (not in gills). CTAC could affect the bioavailability ofpyrene in aquatic systems.Journal of Environmental Science and Health Part A 08/2009; 44(8):791-8. DOI:10.1080/10934520902928610 · 1.14 Impact Factor