Effects of structural and compositional variations of dissolved humic materials on pyrene Koc values

Gauthier, Thomas; Seitz, Werner; Grant, C L

doi:10.1021/es00157a003

Cited by 510 publications

(382 citation statements)

References 21 publications

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“…These values agreed well with the reported K OC for PAHs binding to commercial HS [22]. The observed trend that K OC values for individual HS increased with increasing K OW of PAHs is consistent with the hypothesis of solute distribution [23].…”

Section: Relationship Between Hs Properties and Binding Affinity For supporting

confidence: 91%

Assessing desorption resistance of PAHs in dissolved humic substances by membrane-based passive samplers

Chen

Wang

2010

Journal of Colloid and Interface Science

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a b s t r a c tBinding of hydrophobic organic compounds (HOCs) to humic substances (HS) has significant influence on their fate and bioavailability in an aquatic environment, yet very little is known on the desorption behavior of HOCs in dissolved HS. In this study, triolein-embedded cellulose acetate membranes (TECAMs) were used as passive samplers in dissolved HS-containing solutions to extract the free polycyclic aromatic hydrocarbons (PAHs). The partitioning coefficients (K OC ) of PAHs in dissolved HS from different sources were determined. Then the rapidly desorbable fractions (f rd ) of HOCs in dissolved HS were quantified by a quasi-equilibrium model. Results show that the magnitude of K OC of PAHs correlated strongly with the O/C atomic ratio and molecular weight of HS. The PAHs with lower K OW values desorbed almost reversibly from an aquatic fulvic acid, a sediment humic acid (HA), a lignite HA, and Aldrich HA. However, for strongly hydrophobic chrysene binding to the lignite HA, some extent of desorption resistance was found and attributed to sorption hysteresis as well as steric hindrance. The present study illustrated that the quality of HS and the property of solute may play key roles in determining the desorption reversibility.

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Section: Relationship Between Hs Properties and Binding Affinity For supporting

confidence: 91%

Assessing desorption resistance of PAHs in dissolved humic substances by membrane-based passive samplers

Chen

Wang

2010

Journal of Colloid and Interface Science

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“…The shape of the adsorption isotherms of TMA-, TEA-, and TMH-bentonites are S-type isotherms in Giles' classification, suggesting that the adsorbate-adsorbate interaction is stronger than the adsorbate-adsorbent interaction. The relatively high affinity between phenol and BTMA-and BTEA-bentonite is probably the result of the phenol molecules interacting favorably with the benzene ring in BTMA and BTEA ions through increased p2p type interactions [10,11]. Meanwhile, the saturated uptake of phenol by BTMA-bentonite (34 mg g À1 ) is considerably higher than that by BTEAbentonite (21 mg g À1 ), presumably due to the smaller size of the BTMA ion.…”

Section: Adsorption-flocculation Experimentsmentioning

confidence: 98%

Removal of phenol from water by adsorption–flocculation using organobentonite

Shen

2002

Water Research

157

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“…They can form molecular aggregates, dispersed in different colloidal states in solution or deposited on mineral surfaces [4,5] , and therefore, strongly influence a wide range of environmentally important processes. For example, they may modify the chemical speciation of trace metals, stabilize inorganic colloids via adsorption [6,7] , and significantly impact the fate and transport of hydrophobic organic pollutants in subsurface systems [8][9][10][11][12][13][14][15][16] . A better understanding of their morphology and the underlying adsorption and aggregation processes is therefore of fundamental importance.…”

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confidence: 99%

AFM study on the adsorption and aggregation behavior of dissolved humic substances on mica

Zhou

Lü

et al. 2006

SCI CHINA SER B

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Humic substances constitute the major organic fractions of soils, sediments and natural waters, and play a dominant role in the binding, mobilization, transport and ultimate fate of organic contaminants in subsurface systems. In this paper, two humic acid samples, Guanting and Tianjin, with different origin and chemical compositions have been investigated with AFM imaging for their adsorption and aggregation behaviors on mica. While the Tianjin humic sample is found to form small spheres with 250 to 330 nm in diameter at lower concentrations, irregular loop-chain assemblies of hundreds of nanometer in diameter with the chain width of about 40 nm are dominant for the Guanting humic sample, which may attribute to the more polar aliphatic fractions in the chemical composition in the latter. The heterogeneous and polydisperse nature of humic substances with multiple structural features, such as sponge-like structures, perforated sheets, aggregate of spheres, branches and chain-like assemblies etc., is apparent at higher concentrations for both humic samples, showing morphologically new evidence for the dominant view of the humic dual-mode sorption model. With naphthalene introduced, the assemblies of Guanting humic substances clearly become more compact with significantly narrowed branches and less porous the perforated sheet-like structures. It is indicative of that smaller nanometer scale rings present along the perforated assemblies could potentially represent hydrophobic domains, which may facilitate the adsorption and aggregation of naphthalene onto the natural particle surfaces and therefore lead to an important role of dissolved humic substances in the sorption of environmental pollutants.Keywords: atomic force microscopy (AFM), dissolved humic substances, morphology, aggregation, adsorption.Humic substances (HS) are a category of naturally occurring, biogenic, heterogeneous organic materials found in or extracted from soils, sediments, and natural waters that can generally be characterized as being yellow-to-black in color, of highly variable relative molecular masses, and refractory [1,2] . Derived from a variety of organic precursors (plant biopolymers such as lignin etc.), plant residues and animal debris via both transformation and synthesis processes [3] under the profound geochemical alteration, including the microbiological and chemical degradation, sedimentation and diagenesis as well, humic substances com-AFM study on the adsorption and aggregation behavior of dissolved HS on mica 257 prise highly complex composites of partially or completely degraded biomolecules, carbohydrates, lipids, and proteins etc. However, they cannot be classified into any of the normal, easily defined categories of discrete materials such as proteins, polysaccharides, and polynucleotides. As the major organic constituents of soils, sediments and waters, humic substances are ubiquitous in all terrestrial and aquatic environments. They can form molecular aggregates, dispersed in different colloidal states in solutio...

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Effects of structural and compositional variations of dissolved humic materials on pyrene Koc values

Cited by 510 publications

References 21 publications

Assessing desorption resistance of PAHs in dissolved humic substances by membrane-based passive samplers

Assessing desorption resistance of PAHs in dissolved humic substances by membrane-based passive samplers

Removal of phenol from water by adsorption–flocculation using organobentonite

AFM study on the adsorption and aggregation behavior of dissolved humic substances on mica

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