SOLUBILITY OF DDT AND 2,4-D IN SUPERCRITICAL CARBON-DIOXIDE AND SUPERCRITICAL CARBON-DIOXIDE SATURATED WITH WATER

As part of a program of the assessment of supercritical fluid processes for environmental applications, the solubilities of two priority pollutants in supercritical CO2 were investigated. The solubilities of the pesticide 1,1-bis(4-chlorophenyl)-2,2,2-trichloroethane (DDT) and the herbicide (2,4-dichlorophenoxy)acetic acid (2,4-D) have been determined in supercritical carbon dioxide at 313, 323, and 333 K for pressures ranging from 104 to 208 bar. While saturation of carbon dioxide with water had negligible effect on the solubility of DDT, a solubility enhancement of up to 90% for the highly polar 2,4-D was observed. The data were modeled using the Peng-Robinson equation of state which, with an empirical modification, provides a good description of the behavior of the systems investigated. Preliminary solubility data from a mixed solute bed containing both DDT and 2,4-D are also reported.