【作者】 陈秋飞；

【导师】 张学军；

【作者基本信息】 北京化工大学 ， 材料学， 2008， 硕士

【摘要】 活性碳纤维（Activated Carbon Fibers,ACFs）以其微小的孔径尺寸、狭窄的孔径分布、大的比表面积和表面含氧、氮或其它官能团等优异的性能在污水处理、水深度净化、有机溶剂回收、气体净化、大容量双层电容器和燃料电池等方面得到了广泛的研究,被认为是新世纪最有发展前景的吸附功能材料。本文利用水蒸气钴盐催化活化制备活性碳纤维,通过改变活性碳纤维的制备工艺条件控制其孔径分布,分析了不同工艺条件对活性碳纤维电极电容器的性能影响;建立了活性碳纤维对甲苯动态吸附的测试方法,研究了不同孔径分布的活性碳纤维对甲苯的动态吸附性能以及脱附再生性能。主要工作如下:1、以通用级沥青碳纤维为原料经催化活化制备不同孔径分布的活性碳纤维。对比了未浸渍钴盐活化、浸渍钴盐活化并用稀酸清洗前后活性碳纤维的表面形态和孔结构及其孔径分布,分析了活化剂用量和活化时间对孔结构及其孔径分布的影响。研究结果表明,与未浸渍钴盐活化工艺相比,浸渍钴盐活化使得活性碳纤维表面大孔和中孔结构明显增加;经稀酸清洗后,表面孔隙结构更加丰富;改变活化剂用量可以控制孔径分布;延长活化时间在一定程度上可以提高比表面积,孔径分布保持不变。2、采用直流循环充放电、循环伏安（cyclic voltammogram,CV）以及交流阻抗表征了活性碳纤维电极电化学性能。组装成硬币式两电极模拟电容器测试其循环性能和漏电性能。电极性能的测试结果表明,浸渍钴盐活化并用稀酸清洗所得活性碳纤维电极的比电容高达197F·g^-1,较未浸渍钴盐活化样品提高50%。在1500mA·g^-1的条件下充放电,其比电容为163F·g^-1;经2000次循环后电容量提高了23%。3、采用连续进样气相色谱法测定活性碳纤维对甲苯的动态吸附。研究了相同条件下不同比表面积活性碳纤维开始穿透时间、饱和吸附量与比表面积之间的关系,并与间歇进样气相色谱法进行了比较。研究结果表明,活性碳纤维对甲苯的吸附量与其比表面积之间有很好的相关性。开始穿透时间和活性碳纤维比表面积之间也存在相关性,在一定程度上可作为表征活性碳纤维比表面积差异的指标之一。与间歇进样气相色谱法相比,连续进样气相色谱法操作简单,可高效、快速测定活性碳纤维的穿透曲线,而且更能精确的描述穿透曲线。4、研究了不同孔径分布的活性碳纤维动态吸附甲苯的性能和活性碳纤维对不同浓度甲苯的吸附性能,分析了活性碳纤维孔径分布开始穿透时间和动态吸附量的影响。研究结果表明,甲苯分压很低时,活性碳纤维对甲苯动态吸附量可以达到最大吸附量的80%以上;活性碳纤维对甲苯的动态吸附量与活性碳纤维的比表面积有很好的一致性;钴盐催化活化所制得的活性碳纤维对甲苯最高吸附量达1250mg·g^-1,20次循环吸附脱附再生时对甲苯动态吸附量仍保持在900mg·g^-1以上。更多还原

【Abstract】 Activated carbon fibers （ACFs） are widely used in sewage treatment, water purification, organic solvent recycling, gas purification, electrode of super-capacitor, fuel cell and so on, due to their small pore size and narrow pore-size distribution, high specific surface area and abundant functions, and so ACFs are thought as promising materials in the domain of adsorption and separation in this century. In this study, ACFs were prepared from general pitch-based carbon fibers by catalytic activation method, and how to control the pore-size by varing preparation process conditions was researched. The capacitance proformance of the resultant ACFs were studied, and a method was introduced to test the dynamic adsorption of toluene on ACFs. The adsorption and regeneration properties of different pore-size ACFs were analized. The major work is as following:1. Activated carbon fibers were prepared from general pitch-based carbon fibers by catalytic activation method. The surface morphology of resultant activated carbon fibers before and after diluted acid washing as well as activated carbon fibers without cobalt immersion was observed with SEM, and their difference was investigated. The results showed that the surface of carbon fibers activated with cobalt immersion have more mesopores and macropores than the one without cobalt immersion. More abundant pore structure was obtained by washing the fibers with diluted acid. The specific surface area of activated carbon fibers was increased by prolonging the activate time, but the pore-size of ACFs was not broadened.2. Electrochemical performance of activated carbon fibers as electrodes of super capacitors were characterized by galvanostatic measurements, cyclic voltammograms and AC impedance spectrum analysis. The electrode performance showed that the specific capacitance of activated carbon fibers washed with diluted acid was 197F·g^-1, 50% higher than that of the one without cobalt immersion. At the current density of 1500mA·g^-1, specific capacitance reached 163F·g^-1, and after 2000 DC charge/discharge cycles, the specific capacitance increased by 23%. Carbon fibers activated with cobalt immersion and washed with diluted acid would be promising electrode materials for super-capacitors.3. Continuous sample introduction on GC method was used to test dynamic adsorption of toluene on ACFs. The relationship of breakthrough time, adsorption amount of toluene and specific surface area of activated carbon fibers under the same adsorption condition was analyzed, and comparison was made with interval sample introduction method. The results showed that the adsorption amount of toluene was well related with the specific surface area of activated carbon fibers. The breakthrough time also had a good relationship with specific surface area of activated carbon fibers, and it could be used as one index to characterize the difference of specific surface area. Compared with interval sample introduction method, continuous sample introduction method was very simple to operate, and it was a high efficienct and quick way to test the breakthrough curve of activated carbon fibers, which could describe the breakthrough curve finely.4. The dynamic adsorption of toluene on differnt ACFs and the dynamic adsorption of toluene under different concentration were researched. The results showed that the dynamic adsorption of toluene was 80% of the saturation under low toluene concentration. The adsorption amount of toluene was well related with the specific surface area of activated carbon fibers. The dynamic adsorption of toluene was as high as 1250mg·g^-1 on the ACFs which was preparation by catalytic activation method. The dynamic adsorption of toluene can keep 900mg·g^-1 after 20 cycles.更多还原