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Abstract Monocyclic aromatic hydrocarbons like Benzene, toluene, ethylbenzene and xylene (BTEX) are among environmental pollutants that are considered among chemicals of concern. They are often found in industrial effluents, which when discharged into farmlands end up contaminating the soils. Such happenings warrant the remediation of the soil for environmental sustainability. Solvent extraction, prominent among the techniques employed for this remediation, is limited by the type of solvent used, as volatile organic solvents end up producing secondary pollutants. Various kinds of green solvents like Ionic Liquids (ILs) and Deep Eutectic Solvents (DESs) have been used in this technique as replacements for the conventional ones. In this study, DES made from choline chloride and ethylene glycol in the ratio of 1:2 was synthesized, characterized and used for the remediation of soils contaminated with monocyclic aromatic hydrocarbons (BTEX). Response surface methodology was employed to model and optimize the extraction process. Extraction efficiencies of 76.25, 79.04, 81.93 and 78.66% were obtained for benzene, toluene, ethylbenzene and xylene in a single stage extraction at optimum condition of 45 minutes, 0.841 and 440 rpm for extraction time, solvent mass fraction and mixing rate respectively. Further studies on the solvent regeneration and reuse were conducted. The findings showed that the solvent has capacity to perform effectively in two (2) successive extraction cycles without regeneration, and can undergo up to five (5) cycles upon regeneration without significant loss in its extracting ability. These studies show the possibility of remediating soils contaminated with BTEX using DES under mild extraction conditions.
Almustapha et al. (Sat,) studied this question.