Research and Development of Composite Materials from Transition Metal Oxides and High Temperature Cabonized Charcoalfrom Wood Wastes for Purification of NOx

对人工林疏林、少用树种和其他木材废弃物的利用进行了许多研究，但尚未找到理想的解决办法。与其他研究人员合作，开发了以过渡金属氧化物和木材废料木炭为原料的新型复合材料，用于去除NOx或将其转化为无害气体，开发了三种低能耗、无污染、连续过程的新型炭化系统，用于大规模生产木材木炭。这些产品的质量一直很高。在1000和1400℃下炭化的木粉和活性炭的比表面积明显大于在200,600,1800和2200℃下炭化的木粉。在200,600,1800和2200的温度下，木粉和炭化木材的孔径分布和比表面积没有明显的差异。炭化在1000和1400℃的木粉以及活性炭产生了更多的微孔，其半径在10 nm以下。微孔的形成和消失可能会影响孔隙尺寸分布和比表面积的相似趋势。当炭化温度为600ºC时，NO在所有Nox样品中通过木炭和活性炭后的浓度最低，即600ºC炭化的木粉表现出最好的转化或吸附能力，尽管600ºC炭化的木粉比表面积和孔径分布与1000ºC炭化的木粉和活性炭相比并没有显著大。由此看来，吸附能力的转化与物理性质无关。另一方面，并没有在每个样品中检测到NO_2的浓度。除木粉外，其余木炭均具有良好的NO_2转化或吸附能力。每个炭中检测到的NO浓度都很低。观察到木炭将NO_2还原为NO。当金属氧化物分散木炭在105℃的温度下干燥时，其NO转化率和NO_2还原为NO的效率均低于木炭。在600℃的温度下对复合材料进行热处理，可以提高其转化或吸附NO的能力。其中二氧化钒分散木炭对NO的转化率和吸附率最高。用近波长紫外单色光照射金属氧化物分散木炭，氧化钛分散木炭显著降低NO浓度。波长越短，即随着光能的增加，转化或吸附能力越好。从这个结果可以看出，过渡金属的氧化物作为光催化剂，因为根据这个结果，钒或氧化钛通过光能氧化或还原NO。沸石分散木炭对NO的去除率或其转化为NO或n2的能力随着沸石含量的增加而降低。少

Many research on the utilization of tree plantation thinnings, lesser used species and other wood wastes have been conducted but the ideal solutions have yet to be found. In cooperation with other researchers, in order to develop new composite materials from transtition metal oxides and charcoal from wood wastes for removal of NOx or its conversion into harmless gases, three new carbonization systems for the mass production of wood charcoal which are low-energy, non-pollutant and continuous process were developed. The products are of consistently high quality.Wood powder carbonized at 1000 and 1400ﾟC,and activated charcoal had considerably larger specific surface areas compared to those carbonized at 200,600,1800 and 2200ﾟC.No large difference was observed on the pore size distribution and specific surface areas between wood powder and wood carbonized at 200,600,1800 and 2200ﾟC.Wood powder carbonized at 1000 and 1400ﾟC as well as activated charcoal created more micropores with radii be … More low 10 nm. The formation and disappearance of micropores might have an effect on the similar tendency between pore size distribution and specific surface area.When the carbonization temperature was 600ﾟC,the concentration of NO was the lowest in all the samples of Nox after passing NO through wood charcoals and activated charcoal, that is, the wood powder carbonized at 600ﾟC indicated the best conversion or adsorption ability, even though the specific surface area and pore size distribution of wood powder carbonized at 600ﾟC were not remarkably large compared to wood carbonized at 1000ﾟC and acivated charcoal. It seems that the conversion of the adsorption ability has nothing to do with physical properties. On the other hand, the concentration of NO_2 was not detected among every sample. It is clear that every charcoal except wood powder has good NO_2 conversion or adsorption ability. Very little concentration of NO was detected from every carcoal. It was observed that wood charcoal reduced NO_2 to NO.When metal oxide-dispersed wood charcoal was ovendried at 105ﾟC, the NO conversion and the reduction efficiency from NO_2 to NO decreased compared to wood charcoal. However, the capacity to convert or adsorb NO was improved by heat treatment of the composite at 600ﾟC.Particularly, vanadiumoxide-dispersed wood charcoal showed the highest tendency to convert or adosorb greater amount of NO.When metal oxide-dispersed wood charcoals were illuminated by monochromatic light with near wavelength of ultraviolet rays, titanium oxide-despersed wood charcoal remarkably decreased the concentration of NO.The shorter the wavelength became, that is, as the light energy increased, the better the conversion or adsorption ability. From this result, it was found that oxide of transiton metal performed as photocatalyst since based from the result, vavadium or titanium oxide oxidizes or reduces NO by light energy.Removal of NO or its conversion into NO or N_2 by the zeolite-dispersed wood charcoal were decreased with an increase in content of zeolite on the wood charcoal. Less