The Preparation And Co₂adsorption Properties Of Pan-acf

The activated carbon fiber is a kind of new carbon materials with richporous structure, high specific surface area and narrow pore sizedistribution, and they are present a high CO₂adsorption capacity at ambientpressure and, moreover, they are easy to regenerate. This thesis is focus onincreasing the CO₂adsorption capacity of activated carbon fiber bychanging the pore structure and increasing the specific surface. Because ofcintaining nitrogen, PAN-CF is selected as raw materials. This paper maindiscussed the type of activator, the amount of activator, activation time andavtivation temperature affecting pore strecture and surface area of acticatedcarbon fiber, and pore structure and specific surface area affecting ACFCO₂adsorption properties. The pore structure and specific surface area ofactivated carbon fibers are characterized by iodine adsorption and N2adsorption-desorption. The morphology, chemical element and functionalgroups of activated carbon fiber surface are analyzed through SEM, XPSand FTIR, respectively. The major is as following: 1. ACFs are activated by different activator have different porestructure. The pore of ACF obtained by steam activation is mainmesoporous, while activated by KOH is more micriporous.2. The activated carbon fiber surface area is affected activation process.When activator is KOH, ACF sample activated at850℃and itsactivation time of30min, the iodine adsorption value of ACF is up to1431.8mg/g. Its BET surface area is1235m2/g; micropore surface area is745m2/g; and the micropore volume is0.36cm3/g. As the activationtemperature continues ingcreasing, the iodine value, microporous surfacearea and pore volume of ACF are gradually reduced.3. CO₂adsorption capacities are affected by surface area and pore sizeof ACF. When activator is KOH, ACF sample activated at850℃and itsactivation time of30min, the CO₂adsorption capacity of ACF sample is upto87.29mL/g, at the adsorption temperature of273K and relative pressureP/P0=1.4．After ammonia with high concentration modified, the basic site, theoxygen content and nitrogen content of the activated carbon fiber surfacehave been increased. Moreover, the types of nitrogen-containing functionalgroups have also been increased. Thereby, the CO₂adsorption propertie ofactivated carbon fiber is increasing.