Abstract
The interactions among biosurfactant, soil components and PAHs govern the efficiency of biosurfactant enhanced remediation, which was still poorly studied. In this study, we investigated effects of biosurfactant and soil properties on sorption and desorption of phenanthrene (PHE) and pyrene (PYR) in soil – water systems. Two kinds of soil samples (ditch and under plant) from the same petroleum contaminated site in western Canada were applied. The results indicate that soil organic matter (SOM) was the predominant factor that affects PAHs sorption onto soil. The SOM content in ditch soil was half of that in under plant soil, therefore ditch soil showed less sorption affinity to PAHs than under plant soil. We also examined the combined effects of soil DOM and biosurfactant on desorption of PAHs. The results indicated that more PAHs were desorbed from ditch soil than the under plant soil under the combined conditions. The SOM was still the key factor that determined desorption of PAHs. Besides, competitions among PAHs, DOM and surfactant for sorption sites exist. In high solute concentration system, the competition for sorption site was more severely than low concentration system and more PAHs were sequenced in soil phase in high PAH concentration system. Also in low biosurfactant system, less PAHs were desorbed from soil. The study results should be helpful in broadening knowledge of biosurfactant enhanced bioremediation of PAHs.
Highlights
The interactions among biosurfactant, soil components and Polycyclic aromatic hydrocarbons (PAHs) govern the efficiency of biosurfactant enhanced remediation, which was still poorly studied
We mainly focus on the soil dissolved organic matter (DOM) which has been proven to be the most important factors affecting the behavior of PAHs
Soil and DOM characterization It is known that soil properties such as organic matter, pH, cation exchange capacity (CEC), clay minerals and soil texture will affect the sorption–desorption of PAHs (Hwang 2001; Kuyukina et al 2005; Cao et al 2008; Chen et al 2009a)
Summary
The interactions among biosurfactant, soil components and PAHs govern the efficiency of biosurfactant enhanced remediation, which was still poorly studied. We investigated effects of biosurfactant and soil properties on sorption and desorption of phenanthrene (PHE) and pyrene (PYR) in soil – water systems. Surfactants are amphiphilic compounds and are known to improve the efficiency of desorption of HOCs through enhancing the solubility of HOCs in aqueous systems, facilitating their mobility and bioavailability (Yu et al 2007; Abu-Zreig et al 2003; Cheng and Wong 2006). The efficiency of biosurfactant enhanced bioremediation can be affected by the soil properties due to its potential to be adsorbed by soils, which would enhance contaminant retention in soil, their bioavailability (Rodriguez-Escales et al 2013; Lee et al 2005; Lu and Zhu 2012)
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