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INTERACTIONS BETWEEN ORGANIC COMPOUNDS AND CYCLODEXTRIN-CLAY SYSTEMS
Citation:
Sawunyama, P. AND G W. Bailey. INTERACTIONS BETWEEN ORGANIC COMPOUNDS AND CYCLODEXTRIN-CLAY SYSTEMS. Presented at 222nd American Chemical Society National Meeting, Chicago, IL, August 26-30, 2001.
Impact/Purpose:
Elucidate and model the underlying processes (physical, chemical, enzymatic, biological, and geochemical) that describe the species-specific transformation and transport of organic contaminants and nutrients in environmental and biological systems. Develop and integrate chemical behavior parameterization models (e.g., SPARC), chemical-process models, and ecosystem-characterization models into reactive-transport models.
Description:
Computational and experimental techniques are combined in order to better understand interactions involving organic compounds and cyclodextrin (CD)-clay systems. CD-clay systems may have great potential in the containment of organic contaminants in the environment. This study was undertaken in an effort to determine the extent of adsorption and/or complexation of a model organic compound, methyl orange (MO), in CD-clay systems. The anion form of MO interacts with the clay surface via cationic bridges whereas the cation form is weakly adsorbed by a cation exchange mechanism. In the presence of CD, complexation of MO by CD prevails over MO adsorption by the clay. In acidic media, the presence of CD has a profound influence on the competition between the clay and methyl orange for H+ ions. Also, calculations show that the interactions between clay and CD are minor - - predominantly weak van der Waals interactions.