TY - JOUR

T1 - Inventory of biodegradation data of ionic liquids

AU - Amsel, Ann Kathrin

AU - Olsson, Oliver

AU - Kümmerer, Klaus

N1 - Copyright © 2022 Elsevier Ltd. All rights reserved.

PY - 2022/7/1

Y1 - 2022/7/1

N2 - Ionic liquids (ILs) are increasingly of interest for environmentally open applications. Therefore, completely mineralising ILs are highly desirable. We reviewed the current state of knowledge on ILs' environmental biodegradability and identified research needs. Literature data were evaluated as for applied standard methods (e.g. OECD, ISO, APHA) for biodegradation of ILs in order to get an overview on the validity of the test results received and ILs' biodegradability. 109 studies were evaluated. The ILs were categorised based on the cation's core structure. The biodegradation data was classified according to a traffic light system (red: 0–19% degradation, amber: 20–59% degradation, green: ≥ 60% degradation). Not all studies could be assessed for compliance with the test guidelines due to missing test parameters. Moreover, no study discussed all validation criteria as defined by the test guidelines. Consequently, the reliability and quality of the existing biodegradation data is restrained. With regard to the different cations classified for ≥ 60% biodegradability, phosphonium ILs are the least biodegradable, followed by imidazolium ones. The most ILs that were biodegradable are cholinium ILs. The results indicate the need for more and qualitatively better testing according to standard methods including application and reporting of all validation criteria in order to get reliable data that enables the comparison of the test data and a comprehensive understanding of ILs' biodegradability. Moreover, reliable data allows the selection of sufficiently environmentally biodegradable ILs if an introduction into the environment during use cannot be excluded.

AB - Ionic liquids (ILs) are increasingly of interest for environmentally open applications. Therefore, completely mineralising ILs are highly desirable. We reviewed the current state of knowledge on ILs' environmental biodegradability and identified research needs. Literature data were evaluated as for applied standard methods (e.g. OECD, ISO, APHA) for biodegradation of ILs in order to get an overview on the validity of the test results received and ILs' biodegradability. 109 studies were evaluated. The ILs were categorised based on the cation's core structure. The biodegradation data was classified according to a traffic light system (red: 0–19% degradation, amber: 20–59% degradation, green: ≥ 60% degradation). Not all studies could be assessed for compliance with the test guidelines due to missing test parameters. Moreover, no study discussed all validation criteria as defined by the test guidelines. Consequently, the reliability and quality of the existing biodegradation data is restrained. With regard to the different cations classified for ≥ 60% biodegradability, phosphonium ILs are the least biodegradable, followed by imidazolium ones. The most ILs that were biodegradable are cholinium ILs. The results indicate the need for more and qualitatively better testing according to standard methods including application and reporting of all validation criteria in order to get reliable data that enables the comparison of the test data and a comprehensive understanding of ILs' biodegradability. Moreover, reliable data allows the selection of sufficiently environmentally biodegradable ILs if an introduction into the environment during use cannot be excluded.

KW - Green and sustainable chemistry

KW - Ionic liquids

KW - ISO 14593

KW - OECD 301

KW - Ready biodegradability

KW - Chemistry

UR - http://www.scopus.com/inward/record.url?scp=85127010448&partnerID=8YFLogxK

UR - https://www.mendeley.com/catalogue/5d1a52ed-43c8-39f5-ada7-dbf6735b8c0d/

U2 - 10.1016/j.chemosphere.2022.134385

DO - 10.1016/j.chemosphere.2022.134385

M3 - Journal articles

C2 - 35337825

AN - SCOPUS:85127010448

VL - 299

JO - Chemosphere

JF - Chemosphere

SN - 0045-6535

M1 - 134385

ER -