Influence of water on the supercritical fluid extraction of naphthalene from soil

Supercritical fluid extraction (SFE) is an innovative soil remediation tech nology. To aid system evaluation and design, thermodynamic and kinetic para meters have been measured using a naphthalene contaminated, loamy sand at v arious water contents. The experimental results show that supercritical car bon dioxide can easily extract naphthalene from soil when the water content is below 10%. At low water contents, mass transfer is rapid and the equili brium partition coefficient is independent of the soil's water content. How ever, the overall mass transfer coefficient, (k(ov) a), decreases by at lea st a factor of 200 as the water content increases from 10 to 20%. (C) 1999 Elsevier Science B.V. All rights reserved.