Enhanced Desorption of Phenanthrene from Soils Using Hydroxypropyl‐β‐cyclodextrin: Experimental Results and Model Predictions

Effects of cyclodextrins, humic substances, and rhamnolipids on the washing of a historically contaminated soil and on the aerobic bioremediation of the resulting effluents

“…1). Similar features were also observed by other authors, who used water solutions of cyclodextrins to recover various organic pollutants from contaminated soils (McCray and Brusseau, 1998;Boving et al, 1999;Sheremata and Hawari, 2000;Morillo et al, 2001;Ko and Yoo, 2003). On the basis of COD data (Table II), HS and RL markedly sorbed to the soil, and this was probably the cause for the nonhomogeneous ecotoxicity results collected by analyzing HS-and RL-washed soil with Collembola and Lepidium sativum test organisms (Fig.…”

“…Furthermore, few efforts have been made to improve its performances and to investigate the possibility of using environmental compatible pollutant-mobilizing agents instead of chemical surfactants. Some biogenic products, such as cyclodextrins (Fava et al, , 2003McCray and Brusseau, 1998;Boving et al, 1999;Reid et al, 2000;Sheremata and Hawari, 2000;Morillo et al, 2001;Ko and Yoo, 2003), dissolved humic substances (Iglesias-Jimenez et al, 1997;Conte et al, 2001;Fava and Piccolo, 2002), and microbial surfactants (Noordman et al, 1998;Rosenberg and Ron, 1999;Christofi and Ivshina, 2002), have been recently found to be promising mobilizing agents for hydrophobic aromatic pollutants in different soils, as they conjugated marked pollutantmobilizing effects to nontoxicity and biodegradability. Thus, the use of these agents in lieu of synthetic surfactants may contribute to improving the environmental compatibility of the washing technology, which combines good pollutant recovery yields with few or no negative impacts on the soil native structure and on the biotreatability of the resulting wastewaters.…”

Enhanced Soil Washing of Phenanthrene by Mixed Solutions of TX100 and SDBS

“…Several aspects of single-surfactant behavior may reduce surfactant active concentration according to subsurface conditions ( , ): (i) sorption of surfactants by soils and sediments; (ii) precipitation of anionic surfactant with inorganic salts such as Ca 2+ ; (iii) partitioning of nonionic surfactant to nonaqueous phase liquids (NAPLs); and (iv) coacervation of surfactants to form a separate surfactant-rich phase when the temperature is below the Krafft point of anionic surfactant or above the cloud point of nonionic surfactant, resulting in the surfactant concentration in water below the critical micelle concentration (i.e., no micelles form in aqueous phase). Recently, new surfactant types such as gemini surfactants and surfactant alternatives such as extracellular polymers have been developed, which are compatible with the contaminated medium, meanwhile having high solubilization and mobilization for HOCs ( 10 , − . Limited by production, the practical application and operative cost of these alternatives for remediation may make them not very realistic soon.…”

Enhanced electrokinetic dissolution of naphthalene and 2,4-DNT from contaminated soils

“…There is a tremendous interest in using agents, such as carboxymethyl-␤-cyclodextrin (CMCD) for enhanced removal of pollutants from the contaminated soils by pump and treat remediation [5,6]. Successful examples of CMCD enhanced remediation has been reported for low polarity organic compounds including, polycyclic aromatic hydrocarbons (PAHs), trichlorobenzene, and heavy metals including Cd and Pb [5][6][7][8][9]. However, the conventional remediation methods are ineffective in low to moderate permeability soils, because it is difficult to introduce the cyclodextrin or other reagents into the sub-surface, and to move their complexes with contaminants due to the low hydraulic conductivity of the soils [10].…”