Study On Electrospun Pan Nano-acf And Its Adsorption Property

Electrostatic spinning is a basic approach of preparing nano fibers. As a kind of new type of carbon material, the study on electro-spun polyacrylonitrile nano activated carbon fiber(PAN Nano-ACF)starts relatively late in our country, and there is still less research in its structure and adsorption properties at home and abroad.Based on the previous studies, this paper further investigate the effect of spinning process parameters on fiber diameter and the standard deviation. In addition, the collected optimum conditions are obtained by orthogonal experiment. Different diameter of PAN nanofibers can be manufactured steadily, using the self-designed testing electrostatic spinning device.Based on this, I go on to look at the pre-oxidation process of PAN nanofibers and the optimum pre-oxidation conditions, which providing the foundation of the preparation of high-performance nano-ACF, are proposed through experiment. After that, we can safely draw the conclusion that the best carbonization activation process is under the conditions of active 3 minutes at 600℃by comparison and analysis.SEM, TG-DSC and IR were used as the main characterization methods to systematically research on the the property of original nano PAN fibers, surface morphology, the changes in structure and properties through the stages of preparing PAN Nano-ACF.The results indicate that: (1)The breaking strength and breaking elongation of PAN nano-fiber felt increase with fiber diameter. What's more, under certain conditions in spinning solution volume, the permeability of PAN nano-fiber felt increases with the spinning fluid concentration. And under certain conditions in spinning fluid concentration, the wicking effect of PAN nano-fiber felt increases with the spinning solution volume. (2)The optimum pre-oxidation conditions as follows: warming up to around 100℃at the rate of 5℃/min, every 30℃the heat is turned up at a constant temperature for 20 minutes. The highest temperature rises to 230℃. As the pre-oxidation procession, the surface morphology and molecular chain of PAN nano-fiber can produce a series of changes, which is mainly concerned with the cyclization reaction of macromolecular chain of nano-fiber. (3)Macromolecular chain of pre-oxidative fiber will react with thermal cracking reaction and dehydrogenation after the process of carbonization and activation. In addition, the time of activation must be controled strictly, in order to prepare the high specific surface area PAN nano-ACF. And we should also pay attention to its impacts on the yield of activation. The prepared PAN nano-ACF takes microporous as the predominent type of pores, and the other part of the aperture is in the sub- micropore.The effects of process conditions on the adsorption properties of PAN nano-ACF are studied in this paper. The results show that: (1) PAN nano-ACF will achieve the saturated condition after 160-minute–adsorption benzene. (2)As the extension of time, the PAN nano-ACF will obtain a deeper activated level, following the increasing of specific surface area and pore volume, the broadening of pore and the rising of adsorption platform of N2. (3) The absorbing rates of PAN nano-ACF in iodine and carbon tetrachloride are 1270 mg/g and 85.82 mg/g respectively.