Structural effects of ionic liquids on microalgal growth inhibition and microbial degradation.
In the present study, we investigated structural effects of various ionic liquids (ILs) on microalgal growth inhibition and microbial biodegradability. For this, we tested pyridinium- and pyrrolidinium-based ILs with various alkyl chain lengths and bromide anion, and compared the toxicological effects with log EC50 values of imidazolium-based IL with the same alkyl chains and anion from literature. Comparing determined EC50 values of cationic moieties with the same alkyl chain length, pyridinium-based ILs were found to be slightly more toxic towards the freshwater green alga, Pseudokirchneriella subcapitata, than a series of pyrrolidinium and imidazolium except to 1-octyl-3-methylimidazolium bromide. Concerning the biodegradation study of 12 ILs using the activated sludge microorganisms, the results showed that the pyridinium derivatives except to 1-propyl-3-methylpyridinium cation were degraded. Whereas in case of imidazolium- and pyrrolidinium-based compounds, only n-hexyl and n-octyl substituted cations were fully degraded but no significant biodegradation was observed for the short chains (three and four alkyl chains).
Department of Civil and Environmental Engineering, National University of Singapore, 1 Engineering Drive 2, Singapore, 117576, Singapore.
Thi Phuong Thuy
TP
Pham
School of Chemical Engineering, Chonbuk National University, Jeonju, Jeonbuk, 54896, Republic of Korea. choicejoe@jbnu.ac.kr.
Chul-Woong
CW
Cho
School of Chemical Engineering, Chonbuk National University, Jeonju, Jeonbuk, 54896, Republic of Korea. ysyun@jbnu.ac.kr.
Yeoung-Sang
http://orcid.org/0000-0002-2583-8278
YS
Yun
D000838:Anions; D001673:Biodegradation, Environmental; D002412:Cations; D000460:Chlorophyta / Q000187:drug effects* / Q000254:growth & development; D005618:Fresh Water / Q000737:chemistry / Q000382:microbiology; D007093:Imidazoles / Q000737:chemistry / Q000633:toxicity; D052578:Ionic Liquids / Q000737:chemistry / Q000633:toxicity*; D058086:Microalgae / Q000187:drug effects* / Q000254:growth & development; D059013:Microbial Consortia / Q000187:drug effects*; D011726:Pyridinium Compounds / Q000737:chemistry / Q000633:toxicity; D012722:Sewage / Q000382:microbiology; D014874:Water Pollutants, Chemical / Q000737:chemistry / Q000633:toxicity*
C528768:1-octyl-3-methylimidazolium; D000838:Anions; D002412:Cations; D007093:Imidazoles; D052578:Ionic Liquids; D011726:Pyridinium Compounds; D012722:Sewage; D014874:Water Pollutants, Chemical; C014677:1-methylpyridinium
Algal growth rate; Biodegradation; Environmental assessment; Ionic liquids; Toxicity