Supercritical Extraction of Toxic Organics from Soils

Document Type

Article

Publication Date

2-1-1987

Abstract

Supercritical fluid (SCF) extraction of organic hazardous waste from contaminated soils is a promising new technique for hazardous waste-site cleanup. The ability of SCFs to solubilize heavy molecular weight organics is well-documented. In this investigation, supercritical carbon dioxide (SC-CO2) was used to extract polychlorinated biphenyls (PCBs), 2,2-bis(p-chlorophenyl)-l,l,l-trichloroethane (DDT), and toxaphene from contaminated topsoils and subsoils. An attractive feature of this process is that the C02, being virtually inert, leaves no solvent residue on the processed soil. Supercritical C02at 100 atm and 40 °C was continuously passed through a fixed bed of 10 g of soil. Approximately 70% of the DDT and 75% of the toxaphene can be leached from a topsoil contaminated with 1000 ppm DDT and 400 ppm toxaphene in under 10 min by using SC-C02at a rate of 0.7 g/s. The extraction of contaminated (with 1000 ppm PCBs) subsoil proved to be even more promising, with over 90% PCB extraction in under 1 min at the same C02rate. © 1987, American Chemical Society. All rights reserved.

Publication Source (Journal or Book title)

Industrial and Engineering Chemistry Research

First Page

261

Last Page

268

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