【作者】 王颖；

【导师】 张学军；

【作者基本信息】 北京化工大学 ， 材料科学与工程， 2012， 硕士

【摘要】 活性碳纤维是一种富含微孔结构、比表面积高以及孔径分布集中的新型碳材料，具有吸附量大，吸附效率高，吸脱附速率快等优点。如何通过改变活化工艺来改变其孔结构，提高比表面积，从而提高活性碳纤维的CO₂吸附性能是本论文的研究重点。由于聚丙烯腈基活性碳纤维本身含有氮元素，利于CO₂的吸附,因此本论文选取国产聚丙烯腈基碳纤维为原料，以水蒸气和KOH作为活化剂，研究了不同活化剂种类及用量、活化时间和活化温度所制活性碳纤维的孔结构和比表面积的差异，分析了不同的孔结构和比表面积对CO₂吸附性能的影响。活性碳纤维的孔结构和比表面积通过碘吸附和N2吸脱附实验进行表征,其表面形貌通过扫面电镜进行分析，对样品表面的化学元素及官能团采用X射线光电子能谱和傅里叶红外进行分析。论文成果如下：1、不同活化剂所得活性碳纤维孔隙结构不同，采用水蒸气活化得到的活性碳纤维主要为中孔结构，而采用氢氧化钾作为活化剂制备聚丙烯腈基活性碳纤维可以得到较好的微孔结构。2、活化工艺影响活性碳纤维的比表面积。采用KOH为活化剂，当活化温度为850℃，活化时间为30min时得到的活性碳纤维的碘吸附值最高为1431.8mg/g，活性碳纤维的BET比表面积为1235m2/g，微孔比表面积为745m2/g，微孔孔容为0.36cm3/g。3、活性碳纤维的比表面积及孔径影响CO₂的吸附性能，当采用KOH为活化剂，活化温度为850℃，活化时间为30min时制得的活性碳纤维具有较高的CO₂吸附性能，当吸附温度为273K，吸附相对压力P/P0为1时，吸附量达到87.29mL/g。4、经过高浓度的氨水改性处理后增加了活性碳纤维表面的碱性位，提高了含氧量和含氮量，增加了含氮官能团的种类，从而提高了活性碳纤维的CO₂吸附性能。更多还原

【Abstract】 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.更多还原