Remediation of polychlorinated biphenyl contaminated soils/sediments by supercritical fluid extraction

Supercritical fluid extraction process for removing polychlorinated biphenyl from a DOE job control waste

“…Previous studies have indicated that the solvent power of pure dense C 0 2 is not strong enough to extract persistent pollutants like PCBs from environmental samples, and the use of cosolvents is necessary to enhance recoveries in SFE [6,261. In this study, 5 wt % ethanol is used as cosolvent.…”

“…The common pressure range is 1,500-6,000 psi for these studies. This work utilized 2,000 psi or 4,000 psi as the test pressure, since pressure above 4,000 psi is not needed to enhance the extraction efficiency [6,111. Table 2 shows that increasing pressure from 2,000 to 4,000 psi has little effect on recovery, regardless of the extraction temperature.…”

Supercritical extraction of contaminants from soils and sediments

“…In one example, screening studies of PCB desorption from soils/sediments were conducted in a laboratory scale SCE apparatus to provide basic information in this aspect [45]. The effects of temperature, pressure, cosolvent, water content, and soil/sediment type on PCB desorption were studied.…”

“…For example, a process conceptual analysis at Syracuse University revealed that multidisciplinary studies of solute solubility in SCFs, partition equilibrium, and laboratoryand bench-scale desorption were needed to accomplish the proposed objective [36][37][38][39][40][41][42][43][44][45]. Original laboratory equipment was designed, constructed, commissioned, and used to carry out experiments for all of these fields of interest.…”

Remediation Technologies of Ash and Soil Contaminated by Dioxins and Relating Hazardous Compounds.

“…In addition, the result showed that the removal rate in dry soil is higher than the wet soil. The effect of water content in soil has been comprehensively investigated by Chen et al 25) Their results show that the application of the drying process of soil prior to the SFE-CO 2 remediation was recommended. It was reported that the existence of organic matters in soil decreases the extractability of SFE-CO 2 .…”