Abstract
Comprehensive understanding of biomass solubilization chemistry in aqueous pretreatment such as water-only and dilute acid flowthrough pretreatment is of fundamental importance to achieve the goal of valorizing biomass to fermentable sugars and lignin for biofuels production. In this study, poplar wood was flowthrough pretreated by water-only or 0.05% (w/w) sulfuric acid at different temperatures (220-270°C), flow rate (25 mL/min), and reaction times (8-90 min), resulting in significant disruption of the lignocellulosic biomass. Ion chromatography (IC), Fourier transform infrared (FTIR) spectroscopy, X-ray diffraction (XRD) analysis, and solid state cross-polarization/magic angle spinning (CP/MAS) 13C nuclear magnetic resonance (NMR) spectroscopy were applied to characterize the pretreated biomass whole slurries in order to reveal depolymerization as well as solubilization mechanism and identify unique dissolution structural features during these pretreatments. Results showed temperature-dependent cellulose decrystallization in flowthrough pretreatment. Crystalline cellulose was completely disrupted, and mostly converted to amorphous cellulose and oligomers by water-only operation at 270°C for 10 min and by 0.05 wt % H2SO4 flowthrough pretreatment at 220°C for 12 min. Flowthrough pretreatment with 0.05% (w/w) H2SO4 led to a greater disruption of structures in pretreated poplar at a lower temperature compared to water-only pretreatment.
Original language | English |
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Pages (from-to) | 219-227 |
Number of pages | 9 |
Journal | ACS Sustainable Chemistry and Engineering |
Volume | 4 |
Issue number | 1 |
DOIs | |
State | Published - Jan 4 2016 |
Funding
We are grateful to the DARPA Young Faculty Award No. N66001-11-1-414, The Sun Grant-DOT Award No. T0013GA-Task 8, the National Science Foundation Award No. 1258504, and U.S. DOE-EERE No. DE-EE0006112 for funding this research. Part of this work was conducted at the William R. Wiley Environmental Molecular Sciences Laboratory (EMSL), a national scientific user facility located at the Pacific Northwest National Laboratory (PNNL) and sponsored by the Department of Energy’s Office of Biological and Environmental Research (BER). We also thank Dr. Hongfei Wang and Ms. Marie S. Swita for insightful discussions.
Keywords
- Cellulose
- Decrystallization
- Depolymerization
- Enzymatic hydrolysis
- Flowthrough pretreatment
- Hemicellulose
- Lignin
- Poplar wood