Diamond and pore structure observed in wood charcoal

Conclusions Various carbon structures were observed in the wood charcoal sample: the well known pyrolytic graphite layers, onion-like particles, and diamond structure. It is suggested that wood charcoal carbonized at 700°C is a complex of various carbon structures. The pore structure was observed by electron microscopy, and it is supposed that the microstructure and pores are closely related. Further study of the microstructure during the carbonization process of charcoal is necessary to better understand the characteristic functions of wood charcoal for utilizing it as a source of carbon material.A summary of this study was presented at the 51st annual meeting of the Japan Wood Research Society, Tokyo, April 2001, and the 50th annual meeting of the Society of Materials Science, Osaka, May 2001     

竹重组材的X射线光电子能谱分析

应用X射线光电子能谱分析(XPS)的技术手段,以冷压热固化与热压法两种生产模式的竹重组材为研究对象,分析其竹材表面元素组成及相对含量的变化。试验结果表明,冷、热压法竹重组材表面的C、O及相对含量有明显差异。从C原子结合形式来看,冷压法与热压法相比,冷压法竹重组材CA(-C-C或-C-H)含量增加明显,CB(C-O或C-OH)含量减少明显,CC(C=O)含量减少,CD(O-C=O)变化不大。说明竹材纤维素、半纤维素、木素,以及抽提物含量等化学组分出现不同程度的变化,进而影响二类竹重组材产品的物理力学性能。     

Intercalation of wood charcoal with sulfuric acid

Intercalation of wood charcoal with sulfuric acid (H₂SO₄) was investigated. Carbonized sugi (Japanese cedar) samples were prepared by heating at various temperatures in the range 1700°–2700°C. Electrochemical oxidization was carried out in H₂SO₄ and the feasibility of intercalation was determined. In potentiometric analysis, plateaus appeared for samples carbonized at temperatures above 2300°C. In their X-ray diffraction profiles, the peak at around 26° was shifted to a smaller angle of about 22.4°. These results can be considered as signs of intercalation with acid molecules. Fourier transform infrared analysis of charcoal heated at 2700°C, following washing with water and drying of the sample, showed a band at 1220 cm⁻¹ that was assigned to a sulfonate group. This band was not observed for samples heated at 1900°C. These observations suggest the occurrence of intercalation in the former charcoal, but not in the latter. It is concluded that wood charcoal can undergo intercalation when it has ordered stacking of hexagonal carbon layers. Part of this article was presented at the 55th, 56th, and 57th Annual Meetings of the Japan Wood Research Society, Akita, Hiroshima, and Tsukuba, August 2006, August 2007, and March 2008, respectively, and at the International Conference on Carbon “CARBON 2008,” Nagano, July 2008     

Growth of cone-shaped carbon material inside the cell lumen by heat treatment of wood charcoal

Conclusions With treatment at 2500°C, wood cell walls partially transform into a turbostratic carbon structure, which has an X-ray diffraction peak corresponding to a layer plane spacing of 0.343 nm. Despite this change, there was no apparent change within the cell wall seen by SEM.Cone-shaped carbon material was formed inside the cell lumen after treatment at 2500°C. This is not a feature originating from any wood cell organism and seems to result from vaporized carbon or pyrolysis gases that originate within the cell wall.Part of this work was presented at the 52nd Annual Meeting of the Japan Wood Research Society, Gifu, April 2002     

Reactivity of wood charcoal with ozone

We investigated the resistance of wood charcoal against ozone and estimated the half-life of the charcoal in air. The weight of wood charcoal prepared by the carbonization of Fagus crenata sawdust at 400°C (C-400) was not affected with up to 8.5% ozone while the charcoal prepared at 1000°C (C-1000) burned with 4.9% ozone. Pores with a diameter of approximately 100–200nm were observed on the surface of ozone-treated C-1000 by scanning electron microscopy, although no pores were found in ozone-treated C-400. The peak positions of the C1s spectra and the full width at half maximum of X-ray photoelectron spectrum peaks suggest that C-400 has an amorphous structure composed of aliphatic carbons and small aromatic molecules while C-1000 and activated charcoal (AC) are polyaromatic. It is likely that the aromatic layers of C-1000 and AC were destroyed and the edge carbon atoms were removed as CO or CO₂ by ozone oxidation. We estimated the half-life of C-1000 with ozone in air to be about 50000 years by assuming that the weight of C-1000 decayed exponentially. Thus, it is suggested that wood charcoal is stable on a geological time scale.     

Cone structure of hexagonal carbon sheets stacked in wood cell lumen

Cone-shaped carbon particles were produced inside the cell lumen of sugi (Japanese cedar) charcoal treated at 2500°C. We succeeded in clarifying the structural and morphological features by separating the cone-shaped carbon from the carbonized cell wall by heating to 800°C in air. Cone-shaped carbon is less susceptible to oxidation than the carbonized cell wall. The isolated cone-shaped carbon and carbonized cell wall fracture were observed separately by transmission electron microscopy and selected area electron diffraction. Results revealed that the cone-shaped carbon has a very highly ordered cone structure with regularly stacked hexagonal carbon sheets, whereas the carbonized cell wall has a disordered structure of mosaic-like turbostratic carbon.Part of this work was presented at the 52nd Annual Meeting of the Japan Wood Research Society, Gifu, April 2002     

Chemical changes of wood during steaming measured by IR spectroscopy

Black locust, poplar and spruce samples were steamed at 80°C and 120°C for 48 hours. IR difference spectra and the CIE Lab colour coordinates were measured for determining the chemical changes caused by the steaming. Steaming at 80°C caused only small changes in both IR spectra and colour. But steaming at 120°C produced intensive colour change and well-visible changes in IR spectra. The guaiacyl lignin in hardwoods underwent slight degradation but in spruce suffered substantial degradation during steaming at 120°C. The syringyl lignin absorbing around 1600 cm^?1 did not show any changes, indicating that it is more stable to steaming than guaiacyl lignin. The absorption decrease at 1175 cm^?1 indicated the cleavage of ether linkage in cellulose and hemicelluloses at both steaming temperatures.     

木质炭化物对挥发性有机污染物吸附性能的研究

本文探讨了炭化温度对木材炭化物的得率 ,还原性 ,pH值 ,苯蒸气、三氯甲烷蒸气吸着率的影响。结果表明 ,30 0～ 90 0℃的炭化温度下 ,木炭的得率随着炭化温度升高而下降 ,并在 6 9 8%～ 2 0 6 %的范围内变化。炭化温度为 70 0℃时 ,产物木炭的比表面积最大 ;80 0℃时 ,木炭元素组成中的 (C H) O的摩尔比值最大 ,这意味着该木炭的还原性最大。木炭水溶液的pH值随着炭化温度上升而增加 ,炭化温度小于 5 5 0℃时呈酸性 ,大于 5 5 0℃时为碱性。炭化温度对木炭环境净化能力有显著的影响 ,6 0 0℃炭化得到的木炭对三氯甲烷蒸气的吸附率最大 ,高达8 5 % ,约为 30 0℃时的 5倍 ;80 0℃炭化得到的木炭对苯蒸气的吸附率最大 ,达 5 % ,约为 30 0℃时的 5倍左右。     

Sorption properties of torrefied wood and charcoal

Abstract

Pre-treating biomass by torrefaction is assumed to improve the material's storage properties because of reducing hydrophilicity. In order to assess the effect of sorption on storage properties, the adsorption of water vapour and capillary absorption of liquid water in torrefied and charred spruce and birch were studied. In addition, the chemical changes were evaluated through Fourier Transform Infrared (FT-IR) spectroscopy. Adsorption decreased notably as severity of treatment increased, as was expected due to degradation of the wood constituents, namely hemicelluloses and amorphous cellulose. Capillary absorption increased with increasing severity in spruce samples while birch showed less change, but the maximum volume for absorption increased with both species. FT-IR results showed an increase in aromatic structures that have a role in forming crystalline structures, possibly leading to increased porosity. Torrefied and charred material should not be stored outside, as liquid water absorbs readily into the material, turning it into a suitable substrate for fungi.     

Characterization of sp<Superscript>2</Superscript>- and sp<Superscript>3</Superscript>-bonded carbon in wood charcoal

Japanese cedar (Cryptomeria japonica) preheated at 700°C was subsequently heated to 1800°C and characterized by electron microscopy, X-ray diffraction, and micro-Raman spectroscopy. The degree of disorder of carbon crystallites and the amount of amorphous phase decreased considerably with an increase in heat treatment temperature to 1400°C, while carbon crystallites clearly developed above this temperature, showing that the microstructure of carbonized wood undergoes drastic changes around 1400°C. Besides showing the bands for sp²-bonded carbon, the Raman spectra showed a shoulder near 1100 cm⁻¹ assigned to sp³-bonded carbon. With an increase of heat treatment temperature, the peak position of the Raman sp³ band shifted to a lower frequency from 1190 to 1120 cm⁻¹, which is due to the transformation of sp³-bonded carbon from an amorphous phase to a nanocrystalline phase. These data showed that the microstructure of carbonized wood from 700° to 1800°C consisted of the combination of sp²- and sp³-bonded carbon, which is probably due to the disordered microstructure of carbonized wood. It is suggested that the sp³-bonded carbon is transformed from an amorphous structure to a nanocrystalline structure with the growth of polyaromatic stacks at temperatures above 1400°C.     

STUDY ON WOOD COMPOSITES DENSITY UNIFORMITY BY X-RAY

X-ray is irradiated in some wood composites(multi-layer particleboard.sin-gle-layer particleboard,reconsolidated wood,).According to the gray degree principle(0-255 grade degree)and the corresponding relation between density and gray,X-raynegatives are scanned.The numbers and pictures of every degree density are obtained andaccurate composite densities are counted.     

核磁共振光谱和X射线光电子能谱对纤维低聚糖的分析

1H-1HCOSY和13C-1HHSQC谱对通过Bio-GelP-2柱(2.5cm×125cm)分离制备的纤维三糖、纤维四糖和纤维五糖进行分析。结果表明,在水溶液中纤维低聚糖还原末端C1位α构型与β构型之比(α/β)随聚合度增大而减小,纤维三糖主要是α构型(α/β,0.52),而纤维四糖和纤维五糖主要是β构型(α/β,分别是0.34和0.25)。X射线光电子能谱(XPS)分析表明纤维低聚糖的C1s主要有2种电子结合能,分别为284.8(C1s1,C—O)和286.1eV(C1s2,O—C—O),C1s1与C1s2之比(C1s1/C1s2)随聚合度增大而增大。     

X-ray photoelectron spectroscopy of maleated polypropylene treated wood fibers in a high-intensity thermokinetic mixer

Summary An XPS (X-ray Photoelectron Spectroscopy), also known as ESCA (Electron Spectroscopy for Chemical Analysis) study of wood fiber treated with maleated polypropylene was performed to obtain information on the chemical nature of wood fiber before and after treatment. Wood fiber was treated in a high-intensity thermokinetic mixer with maleated polypropylene at different loading level (relative to wood fiber weight). The XPS results showed that the treatment of maleated polypropylene increased the hydrocarbon concentration of wood fiber, as indicated by the decrease in oxygen-carbon ratio, and the continuous increase of the relative intensity of the component C1 in C1s signal. Based on these values, higher molecular weight maleated polypropylene produced more hydrophobic wood fiber surface than lower molecular weight maleated polypropylene. The decrease in C4 carbon type in C1s signal after treatment suggested that the esterification reaction between wood fiber and maleated polypropylene had not ocurred under the experimental conditions used in this study. Received 5 January 1997     

Mechanical interaction between cellulose microfibril and matrix substance in wood cell wall determined by X-ray diffraction

We investigated mechanical interactions between the cellulose microfibril and the matrix substance in wood cell walls. X-ray diffraction measurements showed that the peak positions of (200) and (004) from cellulose crystals in wood cell walls tended to shift lower and higher toward 2θ, respectively, during water desorption in wood. From our simulations, it is shown that the peak shift of (200) during water desorption is not due to changes in the scattering pattern of the amorphous substance or to lateral expansion of the cellulose crystals due to the Poisson effect in the cellulose microfibril, which is compressed in the molecular chain direction as the amorphous substance shrinks. This suggests that the cellulose microfibril expands transversely during water desorption in the wood cell wall, and that there is a mechanical interaction between the cellulose microfibril and the matrix substance.     

Rapid assessment of wood chemical properties and pulp yield of Eucalyptus camaldulensis in Thailand tree plantations by near infrared spectroscopy for improving wood selection for high quality pulp

Near-infrared (NIR) spectroscopy has been demonstrated as a means for rapid nondestructive determination of the chemical composition and final pulp yield of Eucalyptus camaldulensis in Thailand tree plantations. Multiple linear regression (MLR) analysis and partial least squares (PLS) analysis were introduced to develop statistical models in terms of calibration equations for total pulp yield, screened pulp yield, and contents of -cellulose, pentosans, and lignin in wood. In MLR analysis, a reasonably good calibration equation was found only for pentosans (standard error of prediction (SEP): 0.98%). The PLS analysis improved the accuracy of prediction for every criterion variable, especially for pentosans (SEP: 0.91%) and lignin (SEP: 0.52%). Also, in the case of screened pulp yield, we were able to use such a statistical result as an indicator of the characteristics of the pulp and paper. Thus, NIR spectroscopy could be satisfactorily used as an effective assessment technique for Eucalyptus camaldulensis plantation trees.     

木材软化技术的初步研究

初步研究了两种木材的化学软化技术，通过试验确定了软化剂、软化处理方法。对软化材的化学成分测定和弯曲稳定性的检测结果表明，化学软化剂的配方合理，效果明显，价格便宜，其处理方法简单易行。     

古建木构件化学组分近红外光谱分析

在材种鉴定的基础上,通过近红外光谱(NIRS)定性分析了建成约600 a的木造古建筑木构件的化学组分,结合木构件化学组分定量分析,与现代木材相比较,探讨了近红外光谱技术评价木构件老化的可行性。结果表明:近红外二阶导数特征性谱带反映了木材纤维素以及半纤维素和木质素的基团信息,而其差谱反映出木构件与对照样化学组分变化。这些光谱特征与传统的化学组分定量分析的结果非常一致:纤维素和半纤维素相对含量减少而木质素相对含量增加,与各种组分谱带差谱的增减相对应。此外,在5 882,5 587和5 464 cm-1等谱带处反映的纤维素结晶和半结晶区的光谱信息,差谱观察到木构件与现代材落叶松之间化学组分的不变或减少,其结果与X射线衍射(XRD)方法获得的木材结晶度分析结果相一致。通过NIRS定性分析木构件化学组分及结晶度变化,接近于现场检测方法,使用便携式NIRS,在古建筑木构件端头裸露部位获取光谱信息,能够实现现场对木材化学组分的无损定性评价。本实验结果也表明,除了常规的红外光谱(FT-IR)、XRD分析技术,NIRS技术对于木构件老化状况的评价是一种有潜力的无损检测方法。     

Electromagnetic shielding efficiency of the electric field of charcoal from six wood species

Six wood species were carbonized under various carbonization temperatures and nonoxygen conditions to obtained charcoal. The effects of wood species, rate of temperature rise, and carbonization temperature on the electromagnetic shielding efficiency (ESE) of the electric field were investigated. The wood species used in this study were Japanese cedar, China fir, western hemlock, red oak, fortune paulownia, and Taiwan acacia. Tested materials were carbonized in a high-temperature oven under the following conditions: rate of temperature rise 1°–5°C/min; carbonization temperature 500°–1100°C, with temperature intervals of 100°C; maximum temperature maintained for 1h; and flow rate of nitrogen 300ml/min. The electromagnetic insulation strength system was used to detect the ESE of the electric field of charcoal. It was found that western hemlock and fortune paulownia charcoal showed maximum ESE values of of 36 and 61dB generated at a carbonization temperature of 1000°C. The charcoals derived from four other wood species showed maximum ESE values of 28dB for Japanese cedar, 23dB for China fir, 32dB for red oak, and 38dB for Taiwan acacia, respectively, at a carbonization temperature of 1100°C. The ESE value for fortune paulownia charcoal was similar to those of metal nets. The relations between ESE and logarithmic values of resistivity (log) could be represented by a negatively exponential formula.Part of this report was presented at the 50th Annual Meeting of the Japan Wood Research Society, Kyoto, April 2000