Partitioning of PAHs

Chiou et al. (1998) attributed the enhanced partitioning of PAHs with respect to other HOCs to relatively high compatibility between the cohesive energy densities of PAHs and the aromatic components in SOM. However, the difference in Koc values between soils and sediments is related to the difference in polar group, rather than aromatic carbon, contents (Kile et al. 1999). The authors concluded that the content of polar groups (O-aryl and carboxyl C) has a large negative influence on Koc values, and hence on HOC sorption in soil and sediment. 

Jafvert C.T. (1991). Sediment- and saturated-soil-associated reactions involving an anionic surfactant (dodecyl sulfate). 2. Partition of PAH compounds among phases. Environmental Science and Technology 25 1039-1045. 

McGroddy, S. E., Sediment-pore water partitioning of PAHs and PCBs in Boston Harbor, MA , Ph.D. thesis, Univ. of Massachusetts, Boston, 1993,255 p. 

Theory of Vapor-Particle Partitioning of PAH Compounds in the Atmosphere. Yamasaki et al. (64) treated semivolatile PAHs as inherently vapor-phase materials, existing in the particle phase only because of their tendency to sorb on nonvolatile materials. Under this assumption, the proportion in each phase should vary with the available surface area for sorption and with the ambient temperature. They assumed that sorption followed a Langmuir adsorption isotherm, requiring that there be only a low fractional coverage of the particulate matter with semivolatile material. In this case, competition for sorption sites can be ignored. At equilibrium, the rate of sorption equals the rate of evaporation. They derived this relationship ... 

The significance of soot carbon for atmospheric transport and particulate-gas partitioning of PAH has been assessed in several studies [30-34,52], This exchange is based on the particulate-gas partitioning coefficient Kp... 

Similar to the dynamics of PAHs in the atmosphere, partitioning of PAHs between water and solid particles suspended in solution controls the transport characteristics of the individual PAHs. Partitioning is described by a distribution coefficient, fCj (Lkg x) ... 

Chin, Y. P., and P. M. Gschwend. 1992. Partitioning of PAHs between porewater colloidal organic matter and marine interstitial waters. Environmental Science and Technology 26 1621. 

Simonich and Hites (1994a) studied the partitioning of PAHs between vegetation and the... 

In an investigation of the partitioning of PAHs from coal tar wastes at manufactured gas plant sites into ground water, partitioning of the various fractions of the complex mixture was observed to be inversely related to solubility, with the more soluble compounds partitioning to water more readily (Lee et al. 

A dynamic coupled-column liquid chromatographic technique was used to obtain aqueous solubility data on 11 aromatic hydrocarbons. The aqueous solubility at 25° C was determined for each compound. The precision of replicate solubility measurements was better than 3%. The variation of the solubility of each compound with temperature is expressed in the form of either a quadratic or cubic equation based on a least-squares fit of the solubility to temperature. These equations can be used to interpolate the solubility to within 2% of the experimentally measured values between 5° and 30°C. Enthalpies of solution (AHJ were then calculated from the values obtained and Setschenow constants were calculated from the effect of salinity on solubility. This system was also used to investigate the partitioning of PAHs between aqueous solutions and some sediment samples. 

Polycyclic aromatic hydrocarbons (PAHs), representative HOCs, are very hydro-phobic and have quite low aqueous solubUity. The solubilization/desorption and partitioning of PAHs in soil-water systems have been extensively studied using solubUity-enhancing solutions such as surfactants and cosolvents to achieve effective removal of PAHs from contaminated sites. Recently, a number of laboratory studies on the electrokinetic removal of PAHs have appeared, evaluating the effect of enhancing solution and electrokinetic variables. The field remains underresearched in comparison with metal removal studies. 

Chen, C.-E, Macalady, D.L., and Bunge, A.L. (2004). Soil solubility and soil-water partitioning of PAH contaminated soils determined by solid phase sorption, in preparation. 

Raber B. Kogel-Knabner, I. (1997) Influence of origin and properties of dissolved organic matter on the partition of PAH. Eur J. Soil Sci. 48,443 55. 

The effect of rhamnolipids on the partitioning of the PAHs, naphthalene, fluorene, phenanthrene and pyrene from NAPLs was examined [71]. Enhanced partitioning of the PAHs, occurred even with humic acid-smectite clay complexes, with the exception of naphthalene. The rhamnolipids sorbed onto the solids increasing the amount of solid phase PAHs. These solids are typical of those found in the subsurface and thus indicate the potential for enhancement of the in situ partitioning of PAHs. The equation dC/dt = k(C - C) was used where Cgq is the equilibrium aqueous phase concentration and C the PAH in the aqueous and solid phases. At biosurfactant concentrations above the CMC, k values were lower since there was competition for the PAH between the sorbed biosurfactants and micelles. 

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