Sorption of Phenanthrene by Reference Smectites

• Published in: Environmental science & technology Vol. 35; no. 17; pp. 3456 - 3461
• Main Authors: Hundal, Lakhwinder S, Thompson, Michael L, Laird, David A, Carmo, Ana M
• Format: Journal Article
• Language: English
• Published: Washington, DC American Chemical Society 01.09.2001
• Subjects: Adsorption; Aluminum Silicates; Applied sciences; Biological and physicochemical properties of pollutants. Interaction in the soil; Clay; Earth sciences; Earth, ocean, space; Engineering and environment geology. Geothermics; Environment; Exact sciences and technology; Gastrointestinal Agents - chemistry; Hydrocarbons; Minerals; Organic Chemicals; Phenanthrenes - chemistry; Pollution; Pollution, environment geology; Reference Values; Sediments; Silicates; Soil and sediments pollution; Soils; Temperature; Water Pollutants - analysis; Clay; Sediment water interaction; Phenanthrene; Hydrocarbon; Adsorption isotherm; Adsorption capacity; Hydrophobic compound; Polycyclic aromatic compound; Soil pollution; Sediments; Sorption; Smectite; Reference material; Reaction mechanism; Soil interaction
• ISSN: 0013-936X; 1520-5851
• DOI: 10.1021/es001982a

Fate and behavior of nonionic hydrophobic organic compounds (HOCs) in the environment is mainly controlled by their interactions with various components of soils and sediments. Due to their large surface area and abundance in many soils, smectites may greatly influence the fate and transport of HOCs in the environment. We used phenanthrene as a probe to explore the potential of reference smectites to sorb HOCs from aqueous solution. Batch experiments were used to construct phenanthrene sorption isotherms, and possible sorption mechanisms were inferred from the shape of the isotherms. Our results demonstrate that smectites can retain large amounts of phenanthrene from water. Phenanthrene sorption capacities of the reference smectites investigated in this study were comparable to those of soil clays containing a considerable amount of organic matter. Hectorite exhibited the highest sorption affinity and capacity followed by Panther Creek montmorillonite. The lack of correlation between Freundlich sorption constants (K‘f) and indices of charge or hydrophobicity suggests that sorption of phenanthrene by smectites is primarily a physical phenomenon. Capillary condensation into a network of nano- or micropores created by quasicrystals is likely to be a dominant mechanism of phenanthrene retention by smectites.