Selective Extraction of Organic Contaminants from Soil Using Pressurised Liquid Extraction

Abstract

This study focuses on the application of sorbents in pressurised liquid extraction (PLE) cell to establish a selective extraction of a variety of organic contaminants (polycyclic aromatic hydrocarbons (PAHs), chlorpyrifos, phenol, pentachlorophenol, and sterols) from soil. The selectivity and efficiency of each sorbent depend on the properties of the material, extracting solvent, capacity factor, organic compounds of interest, and PLE operating parameters (temperature, pressure, and extraction time). Several sorbents (silica, alumina, and Florisil) were evaluated and with the proper choice of solvents, polar and nonpolar compounds were successfully separated in two fractions. Nonpolar compounds (PAHs, chlorpyrifos, and pentachlorophenol) were recovered in the first fraction using a polar sorbent such as Florisil or alumina, andn-hexane as eluting solvent, while more polar compounds (phenol and sterols) were recovered in the second fraction using methanol. Silica (5 g) was found to be effective for selective extraction with the satisfactory recoveries for all compounds (PAHs from 87.1–96.2%, chlorpyrifos 102.9%, sterols from 93.7–100.5%, phenol 91.9%, and pentachlorophenol 106.2%). The efficiency and precision of this extraction approach and the existing EPA Method 3545 were compared.

Simultaneous extraction and purification of fucoxanthin from Tisochrysis lutea microalgae using compressed fluids

“…The experiments were proposed following a method described by Osman et al. [14], with some modifications. Briefly, 1.0 g of adsorbent was added at the bottom of the extraction cell and then sand and algal biomass were added as described above (Figure 1B).…”

“…For instance, Osman et al. [14] developed a platform in which PLE and the use of sorbents were integrated to selectively extract several contaminants from soils. As expected, the efficiency and selectivity of the process depended on the properties of each sorbent, organic compounds of interest, and all operating parameters of the PLE.…”

GC-MS method for determining faecal sterols as biomarkers of human and pastoral animal presence in freshwater sediments

“…Conventional extraction methods include the following: ultrasonic bath [37][38][39] which results in relatively fast extractions and does not require expensive instrumentation; saponification followed by liquid extraction [40]; and Soxhlet [15,20,[41][42][43][44][45][46] that, although time consuming, offers high extraction yields. Scientists developed pressurised liquid extraction (PLE) in order to improve the extraction selectivity of target compounds, increase the extraction efficiency as well as reduce time and solvent consumption [47]. The elevated temperatures and pressures when using PLE as an extraction method increase the overall extraction capabilities [47,48].…”

“…Scientists developed pressurised liquid extraction (PLE) in order to improve the extraction selectivity of target compounds, increase the extraction efficiency as well as reduce time and solvent consumption [47]. The elevated temperatures and pressures when using PLE as an extraction method increase the overall extraction capabilities [47,48]. Researchers successfully employed PLE to extract sterols in polluted marine sediments [30,38,45] and biological matrices [49], where sterol concentrations range between 1 and 100 μg g −1 dry weight [6,9,14,15].…”

Rapid sequential separation of sedimentary lipid biomarkers via selective accelerated solvent extraction

“…In both these methods, as well as others (Canosa et al, 2007;Hussen et al, 2007;Ghosh et al, 2011, Osman andSaim, 2013;Net et al, 2014), sediments were ultimately loaded into extraction cells packed with one adsorbent (e.g. silica gel) and then eluted with one solvent [e.g.…”