Ionic Liquids: Bacterial Degradation in Wastewater Treatment Plants

Abstract

Abstract Ionic liquids (ILs) are probably the kind of chemical compounds that have been most intensively investigated in the past 10 years. The potential applications of ILs cover practically all disciplines of chemistry, having received particular attention in separation processes, catalysis, electrochemistry, nanotechnology, and material science. This increasing use promotes the synthesis and application of the new IL compounds at larger scales. As a consequence, a parallel effort has been made by the scientific community to evaluate the potential environmental hazards of ILs. With equal focus, several researches have also made relevant progress in the development of effective treatments to recover or remove ILs from wastewaters and soils. Certainly, the current state of art in the field of ILs results from the cooperative and multidisciplinary work of experts from different scientific fields. In this work, the toxicity and biodegradability of ILs have been revised from the point of view of environmental engineers, centering the analysis on the expected need of managing ILs in a wastewater treatment plant (WWTP). For this purpose, the available standard tests and other methods to evaluate the toxicity of potential xenobiotic compounds are summarized. An overview of the reported toxicities of ILs toward different assays is presented, with particular emphasis in the available guidelines for designing ILs with low toxicity. The standardized tests for determining the biodegradability of xenobiotics are also collected and described. Lastly, the biodegradation behavior of ILs have been summarized, as evidenced in the bibliography, depending on their structural features and the biological systems used in the bioassays. Preliminary analysis, focused on relevant aspects on the toxicity and biodegradability of ILs, was performed in our laboratory using activated sludge. The main aim is to provide useful guidelines for the future development of biological processes for treating wastewater contaminated with ILs in a WWTP.

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Identifiers

DOI

10.1002/9781119951438.eibc2393

Journal

Encyclopedia of Inorganic and Bioinorganic Chemistry

Year

2016