Partitioning of Hydrophobic Organic Compounds to Hydroxypropyl-β-cyclodextrin: Experimental Studies and Model Predictions for Surfactant-Enhanced Remediation Applications

Abstract

Partitioning studies of hydrophobic organic compounds (HOCs) to hydroxypropyl-β-cyclodextrin (HPCD) and one-dimensional transport simulations were conducted to evaluate the feasibility of using HPCD to remove sorbed HOCs in surfactant-enhanced remediation (SER) applications. HOC partitioning to HPCD was very fast, with over 95% of the complexation occurring within 10 min. Some influence of solution chemistry and HOC concentration on HOC−HPCD complex formation coefficients was observed; in general, the magnitude of the effects was similar to that observed previously for a nonionic surfactant (Tween 80) but much less than that for an anionic surfactant (sodium dodecyl sulfate, SDS). HPCD sorption on kaolinite as quantified by both a fluorescence technique and total organic carbon measurements was negligible, indicating no significant affinity of HPCD for the solid phase. Although the HOC solubilization capability of HPCD was lower than that of conventional surfactants such as SDS and Tween 80, transport sim...