| Abstract
| - The application of cyclodextrins in several soil remediationtechnologies has been increasingly studied, but little isknown about their effects on soil physical properties. Oneof the popular soil remediation additives, randomlymethylated β-cyclodextrin (RAMEB), was found to significantlyalter surface and pore properties of soil clay minerals.Therefore, in this paper we studied the effect of variousRAMEB doses on physical properties of selected soils,representing a wide range of clay content (3−49%). Theresults showed that soil physical properties were greatlymodified by RAMEB treatment. Analysis of water vaporadsorption isotherms revealed that RAMEB increased wateradsorption and surface area in sandy soils and decreasedthem in clayey soils. An increase in adsorption energyof water in RAMEB-treated soils indicated that desorptionof nonpolar pollutants can be enhanced. Water vapordesorption isotherms showed that the volumes and radiiof micropores (nanometers range) increased above 1%RAMEB concentration. The micropores became more roughand complex after RAMEB treatment as deduced froman increase in fractal dimensions. The volume of soilmesopores measured by mercury intrusion porosimetry(micrometers range) gradually decreased in most soils withan increase in RAMEB concentration whereas theaverage mesopore radius increased, indicating that finermesopores were blocked by RAMEB. Measurements of thegranulometric composition of soils by sedimentationanalysis showed that the amount of coarse-size soil fractionsincreased on the expense of finer fractions due toaggregation of smaller particles. Behavior of the studiedsoils after RAMEB treatment depended on their clay contentand the dose of cyclodextrin. In clay-rich soils, stronginteractions of cyclodextrins with the soil solid phase governedthe resulting soil properties. In clay-poor soils, thecyclodextrin excess (not interacted with clays) played adominant role. Modification of surface, pore, and aggregationproperties of soils by RAMEB can have a significanteffect in soil remediation technologies.
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