Accelerated solvent extraction of petroleum contaminated sediments

Abstract

Attempts have been made in recent years to find acceptable alternatives to classical soxhlet extraction of petroleum contaminated sediments. One such method that is very promising is accelerated solvent extraction also referred to as high pressure solvent extraction. Utilization of traditional organic solvents at elevated temperatures and pressures facilitate a quick extraction process while minimizing solvent consumption up to 87%. Work was performed on a commercially available accelerated solvent extractor. A certified reference material was first used to investigate the different variable parameter settings and to determine an optimum method for petroleum hydrocarbon contaminated sediments. Once this was determined, the method was verified using another certified reference soil and samples from a field bioremediation test facility. Recoveries for accelerated solvent extractions were 102% of the certified values with standard deviations 28% less than certified standard deviations. ANOVA analysis of the data also indicated that for n-alkanes and aromatics, temperature had a greater influence on recovery than pressure. Extraction recoveries at different pressures were statistically the same, while recoveries at 40'C and I 00 C were significantly higher than other temperatures as determined by the ANOVA analysis. Costs associated with accelerated solvent extraction are 62% of soxhlet in our laboratory. Sample extraction time was shortened from 24 hours per sample to 12 minutes.