Study On Preparation And Properties Of Activated Carbon Fiber

As efficient adsorption materials, Activated Carbon Fiber (ACF) has received highly attention from the scholars at home and abroad in recent years. There are many reports about the study on ACF, but the research in our nation is still not very mature, and the industrialization degree is still not high and its variety is unitary. Now the products of ACF in the market are mainly viscose-based ACF, other varieties of ACF and related products have not yet achieved industrilization, also the specific area is low, which is 1000m2/g in general.Compared with Activated Carbon (AC), ACF has more advantages, such as small fiber diameter, large specific area, well-developed porous structure, small aperture with narrow distribution, big adsorption capacity, rapid desorption speed, easy regeneration and so on. It also has big adsorption capacity and quick adsorption speed to various organic and inorganic gas as well as lots of organic matter and noble metal ions in aqueous solution, and it's also with high purification efficiency, therefore, it has very broad application prospects and demands in numerous areas including environment, medical service and food areas and so on.It's requested that ACF should have different apertures and functions in different application areas, therefore it is very important to study different types of ACF, especially, there's the nitrogen element in PAN-based ACF, Which made it have special application in some areas. So the study on the industrialization of PAN-based ACF and its products has certain practical significance. Especially the development of different kinds and various functions of ACF have much more significance, which will impel the application scope of ACF powerfully.In order to explore the application of ACF in different fields and gradually realize the industrialization of each kind of functionality ACF, we carried on the preparation and performance study on different types of PAN-based ACF in this article. The main research contents and results are as follows:1. Successfully solved the dilemma of making felt with PAN-based ACF. ACF is mainly used on cloth and felt. So we tried to make felts using PANF,OPANF,VFand PCF. Through experiment, we found that non-woven fabric can be made by pure OPANF, but the superficial uniformity is not best. PANF and PCF can not be used to product non-woven fabric alone because of their own weakness. While the mixture of VF and PANF can greatly enhance the performance of fiber felt. Research shows that when the parameters of acupuncture machine are as follows:the needle number is 30, needle depth is 3mm, the fabric needle density is 3000/m, the acupuncture frequency is 200/min and the blending ratio of VF and PANF is 20:80, then we can produce excellent performance non-woven fabric, moreover, we do not use any oil emulsion in the preparation process, therefore the adsorption performance of ACF could not be affected.2. Successfully developed an installment of carbonization and activation to prepare ACF and we haven't seen the similar report about this at home and abroad. Using this installment we have developed different kinds of ACF, furthermore, the cost of this installment is very low which made it possible for the application of ACF in a wider field.3. Using our self-made carbonization and activation installment, we successfully developed micropore ACF. We optimized the experiment parameters through orthogonal experiment. Considering the yield and its practical application, the better process for producing micropore ACF includes:activation temperature:1123K, activation time: 40min, steam quantity:8.30g/min, heating rate:10.0℃/min. According to national standards, we tested the adsorption performance of ACF, the results indicated that the iodine adsorption value is 1231.42mg/g and the carbon tetrachloride adsorption value is 85.93mg/g, which are much higher than the index of coal granular activated carbon of national standards. The benzene adsorption of ACF is 70.73%, which is 46% higher than the ordinary pore viscose-based ACF. Through lots of tests and calculation, we obtained the ACF's specific area was 1689.58 m2/g, pore volume was 0.55ml/g, average aperture was 0.65nm. According to IUPAC's classification of aperture, the ACF in our experiment belonged to micropore ACF.4. Using sol-gelatin/combustion synthesis, we successfully developed two kinds of nanometer powder used to produce mesoporous ACF and antibacterial ACF. Under 900℃, using nitrate and citric acid as raw materials, YAG nanometer powder with high purity and good decentralization were produced. The diameter of the powder is about 60nm. ZnO nanometer powder is prepared through this process:first, prepare gelatin through agitation and heating under 60℃-80℃, made them burning at 350℃and then the sphere granular with similar spaced and size were prepared.5. We successfully developed the mesoporous PAN-based ACF for the first time with YAG nano-powder, and we still haven't seen the relative report about the preparation of mesoporous ACF with this powder. Adding YAG nano-powder into the spinning solution and using our self-made installment, we successfully prepared the mesoporous PAN-ACF through KOH activation method. The research results indicate that the better process of preparing mesoporous PAN-ACF is the solid particle content should be 6%, the activation temperature should be 950℃, activation time should be 40min, and the activator density should be 30%. The average aperture of experimental mesoporous PAN-ACF is 4.5nm, the aperture bigger than 2nm is more than 50%, the specific area is about 1835.24m2/g, and the adsorptive capacity to VB12 is 325.35mg/g.6. Fine antibacterial effect PAN-ACF was successfully developed through adding self-made nanometer zinc oxide antibiotics and Ag-carried antibacterial agent in spinning liquid using our self-made installment. When the activation temperature is 950℃, activation time is 40min, and the activator density is 30%, under such conditions that when antibiotics content is bigger than 6% with regard to the PAN-ACF containing nanometer zinc oxide antibiotics; antibiotics content is bigger than 8% with regard to the PAN-ACF containing Ag-carried antibacterial agent; through the examination of Escherichia coli and Staphylococcus aureus indicate that each kind of ACF prepared in experiment can achieve very ideal antibacterial effect with regard to the ordinary micropore PAN-ACF. Massive experiments indicate that immersion has no affection on the antibacterial ability of PAN-ACF. This is because the antibiotics have already gone deep into the fibers; immersion can not make antibiotics abscission, thus have no effect on ACF's antibacterial ability.7. We are the first to conduct the application study of ACF on protective clothing. The application of ACF in protection field is always the key point studied by researchers of every country, researchers at abroad have successfully developed ACF used to protect poison gas, while at home, we still haven't seen the relative report. Therefore, in this article, we studied the protection effect of ACF to mustard gas using "gas-gas" and "liquid-gas" experiments according to military standards. The research indicates that the ACF prepared in our experiment can significantly get up to the mustard gas protection and the protection time is longer than that of the military standards.8. Activation temperature, activation time, activator density and other parameters have great influence on ACF development. With regards to the preparation of micropore ACF, the increasing of the parameters will promote the increasing of the specific area and aperture of ACF; with regards to mesoporous ACF, the number of mesoporous volume increases along with the increasing of each parameters; with regards to the antibacterial ACF, activation parameters have significant influence on the antibacterial abilities, which is mainly because on the condition that the antibiotics contents are the same, the content of median size pore volume of ACF increases along with the parameters, while the mesoporous displays greatly strengthened adsorptive capacity to the bacterium, so the antibacterial abilities increase greatly. Therefore, quite ideal ACF can be obtained if the technological parameters are controlled reasonably according to practical application situations. 9. There's certain influence of the shape and raw materials of ACF to anti-poison ability. Through research, we found that the protection effect to mustard gas of PAN-ACF felt is better than that of PAN-ACF cloth, and the protection effect of VACF is better. Thickness has obvious influence on the anti-poison time. The anti-poison time increases along with the increase of thickness gradually, but the thickness should not be oversized considering to the comfort.10. Activation time has immediate influence on anti-poison time. The increase of activation temperature and activation time can promote the anti-poison time. Through the analysis on the influence of the structure parameters of ACF on the anti-poison time and overall consideration, we think the protection to mustard gas with specific area of 1758m2/g and thickness of 3mm of VACF is much better. And according to this, we defined the parameters during activation process should be:activation time is 900℃, the proportion of activator used for one time activation is 0.6, activation time is 20min; the proportion of activator for twice activation is 1.3 and the activation time is 30min.In summary, we developed various types of ACF successfully using our self-made carbonization and activation equipment, and optimized the process parameters of activation. According to relevant standards, we tested the adsorption ability, characterized the performance of ACF by using different methods. The equipment has such advantages as simple operation, close to reality, easy industrialization, well utility. If we want to prepare the ACF much more benefit for practical application, the key point is controlling the distribution of the ACF aperture through controlling the activation parameters according to the practical application.