Preparation And Characterization Of Wood Based Reticulated Carbon Foam

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.