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

关于种植园间伐物、较少使用的树种和其他木材废弃物的利用，已经进行了许多研究，但尚未找到理想的解决方案。为了与其他研究人员合作，开发由木材废弃物中的过渡金属氧化物和木炭制成的新型复合材料，用于去除NOx或将其转化为无害气体，开发了三种新的低能耗、无污染、连续化生产木炭的炭化系统。在1000和1400 ℃下煅烧的木粉和在200、600、1800和2200 ℃下煅烧的活性炭的比表面积明显大于在1000和1400 ℃下煅烧的木粉和活性炭。在1000和1400摄氏度下煅烧的木粉以及活性炭产生了更多的微孔， ...更多信息 低10 nm。微孔的形成和消失可能会影响到孔径分布与比表面积的相似趋势，当炭化温度为600 ℃时，NO通过木炭和活性炭后的NO浓度在所有样品中最低，即600 ℃炭化的木粉表现出最好的转化或吸附能力，尽管与1000 ℃下的木粉和活化的木炭相比，600 ℃下的木粉的比表面积和孔径分布并不显著大。吸附能力的转换似乎与物理性质无关。NO_2的浓度在各样品中均未检出。除木粉外，其它活性炭均具有较好的NO_2转化或吸附能力。从每辆车中检测到的NO浓度很低。在105 ℃烘干时，金属氧化物分散的木炭还原NO_2生成NO的转化率和还原效率均低于木炭。然而，通过在600 ℃下对复合材料进行热处理，可以提高转化或吸附NO的能力。特别是，钒氧化物分散的木炭显示出最高的转化或吸附更大量NO的倾向。当金属氧化物分散的木炭被近紫外线波长的单色光照射时，二氧化钛包裹的木炭显著降低NO的浓度。波长变得越短，也就是说，随着光能的增加，转化或吸附能力越好。结果表明，过渡金属氧化物是光催化剂，催化剂中的钒或氧化钛能利用光能氧化或还原NO，随着沸石含量的增加，沸石分散木炭对NO的去除率降低，转化为NO或N_2的量减少。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