title: Pretreatment of eucalyptus with recycled ionic liquids for low-cost biorefinery.
abstract: It is urgent to develop recycled ionic liquids (ILs) as green solvents for sustainable biomass pretreatment. The goal of this study is to explore the availability and performance of reusing 1-allyl-3-methylimidazolium chloride ([amim]Cl) and 1-butyl-3-methylimidazolium acetate ([bmim]OAc) for pretreatment, structural evolution, and enzymatic hydrolysis of eucalyptus. Cellulose enzymatic digestibility slightly decreased with the increased number of pretreatment recycles. The hydrolysis efficiencies of eucalyptus pretreated via 4th recycled ILs were 54.3% for [amim]Cl and 72.8% for [bmim]OAc, which were 5.0 and 6.7-folds higher than that of untreated eucalyptus. Deteriorations of ILs were observed by the relatively lower sugar conversion and lignin removal from eucalyptus after 4th reuse. No appreciable changes in fundamental framework and thermal stability of [amim]Cl were observed even after successive pretreatments, whereas the anionic structure of [bmim]OAc was destroyed or replaced. This study suggested that the biomass pretreatment with recycled ILs was a potential alternative for low-cost biorefinery.
authors.affiliation: School of Environmental Science & Engineering, Huazhong University of Science and Technology, Wuhan 430074, China.
authors.forename: Jikun
authors.initials: J
authors.lastname: Xu
authors.affiliation: School of Environmental Science & Engineering, Huazhong University of Science and Technology, Wuhan 430074, China.
authors.forename: Bingchuan
authors.initials: B
authors.lastname: Liu
authors.affiliation: School of Environmental Science & Engineering, Huazhong University of Science and Technology, Wuhan 430074, China.
authors.forename: Huijie
authors.initials: H
authors.lastname: Hou
authors.affiliation: School of Environmental Science & Engineering, Huazhong University of Science and Technology, Wuhan 430074, China. Electronic address: hujp@hust.edu.cn.
authors.forename: Jingping
authors.initials: J
authors.lastname: Hu
mesh_terms: D000498:Allyl Compounds / Q000737:chemistry*; D002482:Cellulose / Q000737:chemistry; D005052:Eucalyptus / Q000737:chemistry*; D055772:Green Chemistry Technology; D006868:Hydrolysis; D007093:Imidazoles / Q000737:chemistry*; D052578:Ionic Liquids / Q000737:chemistry*; D008031:Lignin / Q000737:chemistry; D059027:Recycling; D012997:Solvents / Q000737:chemistry
chemical_list: C544334:1-allyl-3-methylimidazolium; C525963:1-butyl-3-methylimidazolium; D000498:Allyl Compounds; D007093:Imidazoles; D052578:Ionic Liquids; D012997:Solvents; D002482:Cellulose; D008031:Lignin; C023698:allyl chloride
keywords: Biomass pretreatment; Biorefinery; Enzymatic hydrolysis; Eucalyptus; Ionic liquids recovery