Ionic liquids versus amine solutions in biogas upgrading: the level of volatile organic compounds

Abstract

Background: This article provides information related to the occurrence of volatile organic compounds before and after biogas purification, by means of both aqueous amine solutions and ionic liquids. Results & discussion: Encouraging results were obtained. Under the experimental conditions, 1-butyl-3-methylimidazolium acetate ionic liquid appeared to perform at least two-times better than aqueous amines solutions, since it captured 65 wt% of the identified volatile organic compounds, while aqueous amine solutions retained around 35 wt% only. However, in the case of octamethylcyclotetrasiloxane and dichlorobenzene, aqueous amine solutions rendered better purification performance and diminished the concentration of aforementioned compounds by a factor of five and ten, respectively. Conclusion: This paper sheds new light on ionic liquids as potential separation sorbents and contributes to the understanding of the complex science of biogas upgrading and utilization of renewable energy resources.