205-3 Characterization of Maple Wood Chars Produced At Different Temperatures Using Advanced 13C Nuclear Magnetic Resonance: Quantitative Estimation of Aromatic Cluster Sizes.



Tuesday, October 18, 2011: 8:35 AM
Henry Gonzalez Convention Center, Room 217B, Concourse Level

Xiaoyan Cao1, Joseph Pignatello2, Yuan Li1, Mark Chappell3, Na Chen1, Charisma Lattao4 and Jingdong Mao1, (1)Dept of Chemistry and Biochemistry, Old Dominion University, Norfolk, VA
(2)P.O. Box 1106, Connecticut Agric. Expt. Stn., New Haven, CT
(3)Environmental Laboratory, U.S. Army Corps of Engineers, Vicksburg, MS
(4)Environmental Sciences, Connecticut Agricultural Experiment Station, New Haven, CT
Carbonaceous residues like char have great implications in global carbon cycling, transport and fate of organic contaminants in soil and sediments. Its chemical structural information is important for the understanding of its roles. The present work employed advanced 13C solid-state NMR techniques to characterize maple wood chars produced under N2 at temperatures from 300-700 °C. These techniques included direct polarization/magic angle spinning, 1H-13C long-range dipolar dephasing, and spectral-editing techniques such as dipolar dephasing and 13C chemical shift anisotropy filter. Especially we used the NMR-based protocol to quantitatively estimate aromatic cluster sizes. Our results indicated that the wood char produced at 300 °C were primarily composed of residues of biopolymers such as lignin and cellulose. With higher charring temperature, the spectra of wood chars became dominated by aromatics and aromatic bands became narrower and more symmetric due to the loss of aromatic C-O groups. The aromatic cluster sizes increased with increasing temperature.
See more from this Division: ASA Section: Environmental Quality
See more from this Session: Biochar: Environmental Uses