【作者】 王锐；

【导师】 刘守新；

【作者基本信息】 东北林业大学 ， 林产化学加工工程， 2011， 博士

【摘要】 富勒烯和碳纳米管等新型炭材料的发现,使炭材料的研究倍受关注。作为一种新型炭材料,泡沫炭具有比表面积高、孔隙发达、密度小、耐高温、耐腐蚀等优点,在催化、净化、医疗、航空航天、军事及民用工业有着广泛应用前景。目前泡沫炭的制备主要以煤焦油沥青、石油中间相沥青、高聚物等通过自裂解发泡法、物理发泡法及模板法制备。对泡沫炭原料范围的扩展及制备方法的改进有着重要的现实意义和理论价值。本文旨在于利用木屑这一低成本的可再生资源为原料,经过液化、液化木材树脂化、发泡、炭化、活化等工艺分别制备出多孔泡沫炭、蜂窝状泡沫炭及网状泡沫炭；并将网状泡沫炭与TiO2复合制备复合光催化剂；研究中通过热重分析、X-射线衍射分析、透射电子显微镜、扫描电子显微镜及能谱分析、低温氮气吸附分析及气相甲苯的吸附与降解等方法对制备材料进行了表征。本文对泡沫炭、木材液化研究现状进行了综述,在此基础上介绍了本课题的研究背景、方案、内容、创新点及主要研究方法。研究中以落叶松木屑、桦木木屑、落叶松综纤维素等为原料,通过木材液化、热塑性树脂化及高温裂解炭化等过程,制备了木质基多孔泡沫炭,产物表观密度在0.34～0.50g/cm3之间,经800℃高温处理后,比表面积达到400m2/g以上,平均孔径在1.85～2.35nm之间。以落叶松木屑、桦木木屑、落叶松综纤维素等为原料,通过木材液化、热固性树脂化、物理发泡制备了木质基热固性树脂泡沫,并进一步在高温下炭化,制备了木质基蜂窝状泡沫炭,产物由孔泡壁、韧带及节点组成的不规则六边形或五边形孔泡构成,孔泡尺寸在100～300μm之间,表观密度在0.02g/cm3左右,经800℃高温处理后,比表面积达到400m2/g以上,微观孔隙以微孔为主,平均孔径在1.88～1.99nm之间。以木质基热固性树脂泡沫为前驱体,分别以KOH和H3P04为活化剂,经高温活化制备了木质基网状泡沫炭,产物由相互连接的韧带和节点组成的不规则六边形或五边形孔泡构成,孔泡间相互贯通,表观密度为0.02～0.80g/cm3,经700℃氢氧化钾活化的网状泡沫炭比表面积可达到1100m2/g,孔径呈双峰分布特征,微孔主要集中在0.44～0.45nm,中孔主要集中在3～4.5nm之间,经800℃活化后,比表面积甚至可达到近2000m2/g。以钛酸四丁酯为钛源,以网状泡沫炭为载体,通过溶胶-凝胶法合成了TiO2/泡沫炭复合光催化剂,泡沫炭的高比表面积促进了反应物的富集,泡沫炭抑制了TiO2由锐钛型向金红石型的转变,使TiO2的平均粒径由9.2nm减小到7.1nm,提高了催化剂的比表面积,从而明显提高了TiO2的光催化性能,复合催化剂的气相甲苯降解率最高可达到近90%。复合催化剂的比表面积以微孔为主,最高比表面积为394.97m2/g,微孔表面积最高为339.64m2/g,微孔对于提高催化性能起着更为关键的作用。更多还原

【Abstract】 As materials science and technology continues to evolve, a variety of materials with different properties emerged. The research of carbon materials has attracted considerable attention in the field of materials science, physics and chemical industry with the discovery of some novel carbon materials, e.g., Fullerenes and carbon nanotubes. As a novel carbon materials, Carbon foam has some advantage, for example, a high surface area, developed porosity, light weight, high temperature resistance, and corrosion resistant. Its thermal conductivity, electrical conductivity can be adjusted with different raw materials and preparation technology as requested, so it has been used in catalysis, purification, medical, aerospace, military and civilian industries widely. To date, Carbon foam was prepared by submitting coal tar pitch, petroleum mesophase pitch and polymer to cracking foaming, physical foaming method and template method mainly. Related researches have been focused on the selecting of raw and improving of preparation technology for the past few years.For carbonaceous adsorbents, a large number of open micropores are essential for fast adsorption kinetics. In this thesis, wood sawdust, a low cost and renewable material, was used as raw to prepare wood based porous carbon foam, wood based honeycomb carbon foam, and wood based reticulated carbon foam with a developed pore structure, which underwent liquefaction, resinification of liquefied wood, foaming, carbonization and activation steps. TiO2/carbon foam photocatalysis composite was obtained from reticulated carbon foam then. In research, the samples were characterized by TG and DTG, XRD, TEM, SEM, nitrogen adsorption at77K and adsorption or degradation of toluene gas, and so on.Research status of carbon foam and liquefaction of wood were summarized. Then the research background, programs, contents, innovation point and the main method of this study were led to according to research in these areas.Larch wood sawdust, birch wood sawdust and larch holocellulose were used as raw materials to prepare wood-based porous carbon foam through the liquefaction of wood, thermoplastic resinification, pyrolysis of thermoplastic resins and carbonization process. The bulk density of products was between0.34and0.50g/cm3. The surface area reached to400m2/g or more after the products treated at800℃. The micropore is the main structure and the average pore diameter is between1.85to2.35nm.Wood-based thermosetting resin foam was prepared from larch wood sawdust, birch wood sawdust and larch holocellulose through the liquefaction of wood, thermosetting resinification, physical foaming, then underwent carbonization at high temperature to give wood-based honeycomb carbon foam. The carbon foam was formed by the irregular hexagonal or pentagonal bubble which contained cell wall, ligaments and nodes. The cell size was between100and300μm and the bulk density was about0.02g/cm3. The surface area reached to400m2/g or more after the products treated at800℃. The micropore is the main structure and the average pore diameter is between1.88to1.99nm.Wood based reticulated carbon foam was prepared by potassium hydroxide or phosphoric acid activation method from wood based thermosetting resin foam under high temperature. The carbon foam was formed by the irregular hexagonal or pentagonal bubble interconnected each other. The bulk density was between0.02and0.80g/cm3. Surface area was up to1100m2/g by potassium hydroxide activation at700℃, and twin peaks with micropore of0.44to0.45nm and mesopore of3to4.5nm were shown. Surface area was even up to2000m2/g by activation at800℃.TiO2carbon foam photocatalysis composite was given by sol-gel method through tetrabutyl titanate deposited on the reticulated carbon foam. Concentration of reactants was promoted due to high surface area of carbon foam, and carbon foam inhibited TiO2from anatase to rutile transformation and the average particle size decreased from9.2nm to7.1nm. Surface area of catalyst and photocatalytic activity of TiO2increased obviously. The highest degradation percentage to toluene gas was up to90%on photocatalysis composite. The micropore is the main structure. The highest surface area was394.97m2/g and the micropore area was339.64m2/g. Micropore played a more critical role for improving photocatalytic activity.更多还原