Remediation of Soils Contaminated with Total Petroleum Hydrocarbons and Polycyclic Aromatic Hydrocarbons: Extraction with Supercritical Ethane

Abstract

In this work two natural certified soils were extracted with supercritical ethane. One sample was polluted with total petroleum hydrocarbons (THP−soil) and the second one with polycyclic aromatic hydrocarbons (PAH−soil). The extraction studies were carried out using a high-pressure experimental device constructed in our laboratory. The extraction conditions for the TPH−soil were 27.1 MPa and 308.15 K, whereas those for the PAH−soil were 23.7 MPa and 308.15 K. Four independent extractions were performed on each test soil varying the volume of solvent: 10, 20, 30, and 40 L. Infrared spectroscopy was used to quantify the hydrocarbons in the residues after supercritical extraction of the TPH−soil, whereas high-performance liquid chromatography was employed, with a photodiode array detector and a fluorescence detector, to analyze seven polycyclic aromatic hydrocarbons (PAHs) in the residues after supercritical extraction of the PAH−soil. The extraction results show that there is a reduction of hydrocarbons of 76% using 10 L of ethane while the reduction is 90% using 40 L of ethane for the TPH−soil sample. For the sample of PAH−soil there is a reduction greater than 80% for the concentration of six of the seven PAHs studied. Naphthalene behaves as a refractory compound; hence, it presents the lowest reduction in concentration.

Remediation of Petroleum-Contaminated Soil and Simultaneous Recovery of Oil by Fast Pyrolysis

“…Most petroleum contaminants are biodegradable over time, and many researchers have reported the feasibility of PCS bioremediation with microbes or plants. , The major challenge for PCS bioremediation is the poor bioavailability and long degradation period because of the inefficient air permeability of PCS and mass transfer efficiency . Additionally, the existence of some components that are biologically recalcitrant and seriously toxic, such as polycyclic aromatic hydrocarbons, decrease the bioremediation efficiency. , To reduce the remediation time, a series of physicochemical techniques, such as thermal desorption, washing, , extraction, , and chemical oxidation, , have been developed for soil remediation. Despite the efficiency of these methods, the pollution problems are not fully addressed because the pollutants are merely transferred and post-treatments are still necessary.…”

“…10 Additionally, the existence of some components that are biologically recalcitrant and seriously toxic, such as polycyclic aromatic hydrocarbons, decrease the bioremediation efficiency. 11,12 To reduce the remediation time, a series of physicochemical techniques, such as thermal desorption, 13 washing, 14,15 extraction, 16,17 and chemical oxidation, 18,19 have been developed for soil remediation. Despite the efficiency of these methods, the pollution problems are not fully addressed because the pollutants are merely transferred and post-treatments are still necessary.…”

Super-Critical Fluid: An Overview on Analytical Applications

“…and thereby decreases the uncertainty obtained in the analysis, results, and become less labor-intensive [49]. SFE has been used for selective extraction of various organochlorine and organophosphorus pesticides [50], polycyclic aromatic hydrocarbons [PHAs] [51], and different types of organic pollutants [52] from various matrices such as sediments, soils, food compositions, and plant tissues (Table 2). PAHs are known as mutagens and carcinogens and they are mainly considered environmental pollutants [53].…”

Surfactant-Enhanced Solubilization and Simultaneous Degradation of Phenanthrene in Marine Sediment by Electro-Fenton Treatment

“…They are hydrophobic pollutants well-known as carcinogens or mutagens . Although many physical–chemical and biological treatments have been developed for PAHs environmental remediation, − the main drawback of PAHs treatment is their low solubility, and thus the use of solubilizing agents as surfactants is becoming the first step for PAHs remediation …”