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-spunpolyacrylonitrile nano activated carbon fiber（PAN Nano-ACF）startsrelatively late in our country, and there is still less research in its structureand adsorption properties at home and abroad.Based on the previous studies, this paper further investigate theeffect of spinning process parameters on fiber diameter and the standarddeviation. In addition, the collected optimum conditions are obtained byorthogonal experiment. Different diameter of PAN nanofibers can bemanufactured steadily, using the self-designed testing electrostaticspinning device.Based on this, I go on to look at the pre-oxidation process of PANnanofibers and the optimum pre-oxidation conditions, which providingthe foundation of the preparation of high-performance nano-ACF, areproposed through experiment. After that, we can safely draw theconclusion that the best carbonization activation process is under theconditions of active3minutes at600℃by comparison and analysis.SEM, TG-DSC and IR were used as the main characterizationmethods to systematically research on the the property of original nanoPAN fibers, surface morphology, the changes in structure and propertiesthrough the stages of preparing PAN Nano-ACF.The results indicate that:（1）The breaking strength and breakingelongation of PAN nano-fiber felt increase with fiber diameter. What’s more, under certain conditions in spinning solution volume, thepermeability of PAN nano-fiber felt increases with the spinning fluidconcentration. And under certain conditions in spinning fluidconcentration, the wicking effect of PAN nano-fiber felt increases withthe spinning solution volume.（2）The optimum pre-oxidation conditionsas follows: warming up to around100℃at the rate of5℃/min, every30℃the heat is turned up at a constant temperature for20minutes. Thehighest temperature rises to230℃. As the pre-oxidation procession, thesurface morphology and molecular chain of PAN nano-fiber can producea series of changes, which is mainly concerned with the cyclizationreaction of macromolecular chain of nano-fiber.（3）Macromolecular chainof pre-oxidative fiber will react with thermal cracking reaction anddehydrogenation after the process of carbonization and activation. Inaddition, the time of activation must be controled strictly, in order toprepare the high specific surface area PAN nano-ACF. And we shouldalso pay attention to its impacts on the yield of activation. The preparedPAN nano-ACF takes microporous as the predominent type of pores, andthe other part of the aperture is in the sub-micropore.The effects of process conditions on the adsorption properties ofPAN nano-ACF are studied in this paper. The results show that:（1） PANnano-ACF will achieve the saturated condition after160-minute–adsorption benzene.（2）As the extension of time, the PAN nano-ACFwill obtain a deeper activated level, following the increasing of specificsurface area and pore volume, the broadening of pore and the rising ofadsorption platform of N₂.（3） The absorbing rates of PAN nano-ACF iniodine and carbon tetrachloride are1270mg/g and85.82mg/grespectively.