Do All Carbonized Charcoals Have the Same Chemical Structure? 2. A Model of the Chemical Structure of Carbonized Charcoal
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- 作者：Jared Bourke ; Merilyn Manley-Harris ; Chihiro Fushimi ; Kiyoshi Dowaki ; Teppei Nunoura ; Michael Jerry Antal ; Jr.
- 刊名：Industrial & Engineering Chemistry Research
- 出版年：2007
- 出版时间：August 29, 2007
- 年：2007
- 卷：46
- 期：18
- 页码：5954 - 5967
- 全文大小：884K
- 年卷期：v.46,no.18(August 29, 2007)
- ISSN：1520-5045
文摘
Charcoals and carbonized charcoals (i.e., biocarbons) were prepared from a wide variety of biomass substrates,including pure sugars containing five- and six-membered rings with furanose and pyranose configurations,lignin, agricultural residues (corncob and nut shells), and a hard wood. These biocarbons were subject toproximate and elemental analysis, gas sorption analysis, and analysis by inductively coupled plasma massspectroscopy (ICP-MS), scanning electron microscopy (SEM), X-ray diffraction (XRD), electron spin resonance(ESR), 13C cross-polarization magic-angle spinning (CPMAS) NMR, and matrix-assisted, laser desorptionionization coupled with time-of-flight mass spectroscopy (MALDI-TOF MS). All the carbonized charcoalscontained oxygen heteroatoms, had high surface areas, and were excellent conductors of electricity. Dopingthe biocarbon with boron or phosphorus resulted in a slight improvement in its electrical conductivity. TheXRD analysis indicated that the carbonized charcoals possess an aromaticity of about 71% that results fromgraphite crystallites with an average size of about 20 Å. The NMR analysis confirmed the highly aromaticcontent of the carbonized charcoals. The ESR signals indicated two major types of carbon-centered organicradicals. MALDI-TOF spectra of the charcoals and carbonized charcoals greatly differed from those of syntheticgraphite. The biocarbons contained readily desorbed discrete ions with m/z values of 317, 429, 453, 465,685, and 701. These findings were employed to develop a model for the structure of carbonized charcoal thatis consistent with the biocarbon's oxygen content, microporosity and surface area, electrical conductivity,radical content, and its MALDI-TOF spectra.