Preparation, Configuration And Properties Characterizion Of Activated Carbon Fiber From Liquefied Wood By Physical Activation

As an ideal and efficient adsorption material, activated carbon fiber gained its development on the basis of carbon fiber industry which was made from polyacrylonitrile, pitch and coal tar. With the gradual depletion of fossil resource, carbon fiber has been in such great shortage that it is of great importance to research and exploit renewable resources as a substitute for fossil resource in order to produce activated carbon fiber in many areas.In this paper, the author took the Southern fast-growing plantation species of Eucalyptus wood as the source material, studied the conditions of carbonization and activation to make activated carbon fiber out of liquefied wood through orthogonal test. Besides, the author also explicated the process of carbonization and physical activation process of the preparation of activated carbon fiber from liquefied wood; The author adopted SEM, Specific surface area and pore size distribution test instrument and analyzed the morphological characteristics, BET specific surface area and pore structure respectively; what’s more, the author also adopted XRD、FTIR、XPS to analyze the crystal structure, surface functional groups and component of physical activation of liquefied wood activated carbon fibers; Other than the above, the author also tested the density, pH value, and iodine adsorption value of activated carbon fiber from liquefied wood. The results are as follows:1. Carbon precursor fiber from liquefied wood could be carbonized when the carbonized temperature was800℃, the heating rate was3℃/min and the carbonized time was180minutes. Through this process, wood liquefaction material carbon fiber was made while its yield was53.95%and its iodine sorption value was552.18mg/g, whose specific surface area and total pore volume were1084.125m2/g0.413cm3/g respectively. Besides, its surface was rather smooth and micro porous and mesoporous pore structure could be found in it, most of the aperture of which was less than<2nm and its pore size distribution was quite narrow.2. The optimum preparation physical activation process of carbon fiber from liquid wood were as follows:the activation temperature was900℃, the heating rate was3℃/min, the flow rate of water vapor was3ml/min and the activation time was80minutes. Under such technological conditions, activated carbon fiber from liquefied wood could be made with a yield of15.06%, a BETspecific surface area of2917.72m2/g and the iodine adsorption of819.35mg/g.3. There was an ablation effect on graphite crystallite level of carbon fiber from liquefied wood in the activation of water vapor when the activated temperature was700℃. There were a few defects like bubbles and attachments on the surface of activated carbon fiber from liquefied wood. The higher the temperature was, the more serious the ablation was, and all this could lead to the broadening of the channels of the activated carbon fiber which was prepared. The more the developed pore structure was, the cleaner the surface was. The erosion of the surface of carbon fiber from liquefied wood was improved in the activation of water vapor which was due to the increasing of activated temperature. The surface of the ablated part took away some of oxygen-containing functional group was taken away by part of surface which was ablated while the ratio of O/C was decreased gradually.4. A large number of microporous, some mesoporous and a few macropores existed in activated carbon fiber from liquefied wood. Its specific surface area, total pore volume and pore volume, microporous volume together with iodine sorption value tended to increase with the increasing of activation temperature.5. Developed pore structure, whose density was less than1g/cm3, was formed due to the reaction between the activated carbon fiber from liquefied wood and water vapor during activation process. C-O, whose pH value is faintly acid, is easy to break when carbon fiber from liquefied wood is activated in high temperature under the condition of water vapor. Other acidic oxygen functional groups such as hydroxyl, ether group and carbonyl were formed.6. The diameter of activated carbon fiber from liquefied wood was decreased constantly with the rising of activation temperature. There was a trend that the tensile strength and elastic modulus of activated carbon fiber from liquefied wood was decreased linearly with the increasing of temperature. Its activation temperature was increased from700℃to900℃while its tensile strength and elastic modulus were decreased respectively by74.89%and93.58%from133.05MPa and0.47GPa.