Sorption of polycyclic aromatic hydrocarbons to mineral surfaces

Abstract

Minerals contribute crucially to the retention of polycyclic aromatic hydrocarbons (PAHs) in subsurface environments. To investigate the sorption behaviour to mineral surfaces batch sorption experiments were conducted using three PAHs (phenanthrene, pyrene, benzo(a)pyrene) and three mineral sorbents that were representative of subsurface materials (quartz, goethite-coated quartz, quartz-montmorillonite mixture). Sorption kinetics showed an instantaneous, considerable PAH sorption to all minerals, except for phenanthrene sorption to quartz at small aqueous-phase concentrations. Apparent sorption equilibrium was achieved after 4 hours of contact time. The sorption characteristics were fitted to six isotherm models by applying Monte Carlo simulation and nonlinear regression. Best-fit models were obtained by a model discrimination approach. Phenanthrene and pyrene sorption were best described by the Freundlich isotherm model, with the exception of phenanthrene sorption to quartz (linear isotherm). Good fit results for quartz were also obtained for the combined linear-Freundlich isotherm. Benzo(a)pyrene sorption to all minerals followed linear high-affinity isotherms. In the case of phenanthrene and pyrene, the Monte Carlo simulations resulted in mean values with small standard deviations for the isotherm parameters, indicating a negligible influence of the experimental uncertainties on the accuracy of the fitted parameters. For phenanthrene, (i) linear isotherms to quartz and goethite-coated quartz and (ii) a nonlinear concaveshaped isotherm to quartz-montmorillonite, assuming a pore-filling process to micropores formed by clay aggregates, were confirmed. For pyrene, nonlinear convex-shaped isotherms to the mineral surfaces were assessed. A specific sorption affinity of pyrene to the goethite surface indicated a non-covalent cation-p interaction. Small sorption affinities to quartz-montmorillonite support an unfavourable partitioning into the adjacent water.

Organic contamination versus mineral properties: competing selective forces shaping bacterial community assembly in aquifer sediments

“…Here, it needs to be considered that petroleum hydrocarbons show a lower sorption to quartz than to mica (Kleineidam et al 1999a,b, Müller et al 2007). Additionally, already at a low sediment organic carbon (OC) content, PAHs effectively sorb to surfaces, with mica, the iron-coated quartz, and silt and clay significantly exceeding the OC content of TQ (Müller et al 2007, Anneser et al 2010. It thus can be assumed that the PAH loading was much higher on mica and the remaining sediment fraction (sediment that was depleted in TQ and mica) than on the TQ.…”

Lixiviação de naftaleno em solos urbanos da região metropolitana do Recife, PE

“…Conforme demonstrado na literatura (Tunega et al, 2009;Muller et al, 2007), tem sido observada uma forte tendência de sorção de compostos hidrofóbicos, como o naftaleno, com os óxidos de ferro, os quais contribuem de forma significativa junto com a matéria orgânica para a retenção do naftaleno no referido solo.…”

Health risk assessment of mixed contaminants: Interaction of metals on the uptake of polycyclic aromatic hydrocarbons in human liver cells

“…Soils spiked with PAHs were aged over 7 to 90 days. During the ageing process PAHs may interact with ligands in soils resulting in changes to its bioaccessibility (Zhu et al, 2014;Hundal et al, 2001;Müller et al, 2007). In this study, the bioaccessibilities of B[a]P, Nap, Phe and Pyr continued to decrease over the 90 days of exposure (Table 7.3 -7.10).…”

“…The United States Environmental Protection Agency (US EPA) has listed 16 un-substituted PAHs as priority contaminants as these are most widely found in the environment (Jahin et al, 2009) and considered markers of urban activities (Peng et al, 2013 Varying physicochemical properties of soils can influence the BAC and BA of PAHs. The sorption of PAH to soil is reported to be influenced by the soil organic matter (SOM), total organic carbon (TOC) and clay content (Müller et al, 2007;White et al, 1999). A decrease in extractability and bioavailability of PAHs was observed with increasing TOC, while soils with higher content of sand had comparatively higher BAC of PAHs (Meyer et al, 2015).…”

“…Physical diffusion of PAHs into micropores of soils have been investigated and in such studies inaccessibility of PAHs to even the smallest microorganisms has been reported (Müller et al, 2007;Wu and Gschwend, 1986). Therefore, both the physicochemical properties of PAHs and soil properties are important in determining BAC and BA of PAHs.…”