Effect of thermodynamics properties of supercritical fluid on the extraction efficiency of phenanthrene from soil-porous media

Abstract

Supercritical Fluid Extraction (SFE) is the process of separating one component (the extractant) from another (the matrix) using supercritical fluids that is CO2 as the extracting solvent. Clay soils have specific properties that cause difficulty in the assessment and remediation of contaminated sites. Furthermore, polyaromatic hydrocarbons, when present in soil, are difficult to extract due to their nonpolar, high molecular weight characterization. In this study, the su-percritical fluid (carbon dioxide) extraction (SFE) technique, with methanol modifier, was used for removal of PAHs (phenanthrene) from kaolinite, illite, and mixture of soil with sand soils. The impact of thermodynamics properties of supercritical fluid enthalpy, entropy and internal energy on the removal efficiency of PAHs from clayey soils were investigated. The results of this investigation show that the extraction efficiency increases with decreasing the heat content of supercritical fluid. The recovery decreases with increasing the entropy This is due to the soil properties such as the size of the pores, mineral content and surface area of the soil