Cyclodextrin‐Enhanced Solubilization of Organic Contaminants with Implications for Aquifer Remediation

Publisher Website
Google Scholar
Abstract
Reagents that enhance the aqueous solubility of non‐aqueous phase organic liquid (NAPL) contaminants are under investigation for use in enhanced subsurface remediation technologies. Cyclodextrin, a glucose‐based molecule, is such a reagent. In this paper, laboratory experiments and numerical model simulations are used to evaluate and understand the potential remediation performance of cyclodextrin. Physical properties of cyclodextrin solutions such as density, viscosity, and NAPL‐aqueous inter‐facial tension are measured. Our analysis indicates that no serious obstacles exist related to fluid properties that would prevent the use of cyclodextrin solutions for subsurface NAPL remediation. Cyclodextrin‐enhanced solubilization for a large suite of typical ground water contaminants is measured in the laboratory, and the results are related to the physicochemical properties of the organic compounds. The most‐hydrophobic contaminants experience a larger relative solubility enhancement than the less‐hydrophobic contaminants but have lower aqueous‐phase apparent solubilities. Numerical model simulations of enhanced‐solubilization flushing of NAPL‐contaminated soil demonstrate that the more‐hydrophilic compounds exhibit the greatest mass‐removal rates due to their greater apparent solubilities, and thus are initially more effectively removed from soil by enhanced‐solubilization‐flushing reagents. However, the relatively more hydrophobic contaminants exhibit a greater improvement in contaminant mass‐removal (compared with water flushing) than that exhibited for the relatively hydrophilic contaminants.