title: Enhancement of anaerobic digestion of grass by pretreatment with imidazolium-based ionic liquids.
abstract: In this work, the toxicity of imidazolium-based ionic liquids (ILs) and the enhancement of high-solid anaerobic digestion by pretreatment were studied. Compared with [Bmim]Cl, [Bmim]OAc and [Bmim]BF4, [Bmim]PF6had the highest toxicity. When the mass ratio of [Bmim]PF6to grass was higher than 1:10, biogas was not produced within 30 days. The ability to remove lignin and hemicellulose followed the sequence of [Bmim]OAc, [Bmim]Cl, [Bmim]BF4and [Bmim]PF6. The crystallinity index of grass pretreated with [Bmim]OAc, [Bmim]Cl, [Bmim]BF4and [Bmim]PF6reduced by 73.83%, 54.44%, 17.52% and 7.47%, respectively. The pretreatment with ILs enhanced the methane yield of grass by reducing crystallinity and particle size. The grass pretreated with [Bmim]OAc had the highest methane yield, about 221 mL/g volatile solids, due to its good lignin removal ability and relative low toxicity. After 10 times recycling, the cumulative methane yield of grass pretreated by recycled [Bmim]OAc decreased by 11.95%.
authors.affiliation: a NUS Environment Research Institute , National University of Singapore , Singapore , Singapore.|b State Key Laboratory of Multi-Phase Complex Systems , Institute of Process Engineering, Chinese Academy of Sciences , Beijing , People's Republic of China.
authors.forename: W
authors.initials: W
authors.lastname: Li
authors.affiliation: b State Key Laboratory of Multi-Phase Complex Systems , Institute of Process Engineering, Chinese Academy of Sciences , Beijing , People's Republic of China.
authors.forename: G
authors.initials: G
authors.lastname: Xu
mesh_terms: D056804:Biofuels; D007093:Imidazoles; D052578:Ionic Liquids / Q000633:toxicity*; D008031:Lignin; D008697:Methane; D006109:Poaceae
chemical_list: D056804:Biofuels; D007093:Imidazoles; D052578:Ionic Liquids; C029899:imidazole; D008031:Lignin; D008697:Methane
keywords: Ionic liquids; anaerobic digestion; biogas; hydrolysis; pretreatment