分子筛型 PAN-ACF制备及表面结构的 XPS研究

摘要

A new method of liquid impregnation combining air oxidition is employed to modify the surface and pore structure of PAN-based activated carbon (PAN-ACF) under moderate condition.By this method,a molecular sieve type PAN-ACF is prepared having high selectivity to separate N2 from O2.TGA DGA,electronic balance and XPS are used to characterize the performance and surface chemistry of the samples.The results show that PAN-ACF impregnated with condensed coal tar has a slight weight loss during 100～ 400 ℃ ,the benzenoid and heterocyclic compound graft with carbon fiber by the aid of oxygen molecule to tailor the pore and surface structure of fibers.After oxidizing by air,the selectivity and adsorptive capacity of PAN-ACF are improved significantly,the selectivity reaches 5.6 of N2/O2.There are many kinds of function group such as hydroxyl group,ether,carbonyl and carboxyl after the impregnation of PAN-ACF with condensed coal tar and oxidized by air,during oxidition the content of various function group changes,graphite-like carbon increases with the increase of impregnated concentration.%以聚丙烯腈基活性炭纤维（ PAN- ACF）为原料 ,首次采用液相浸渍结合空气氧化的方法 ,在较为温和的条件下改变原料的表面结构和孔隙结构 ,制备出具有分离 N2/O2性能的分子筛型 PAN- ACF.采用 TGA- DTA、电子天平及 XPS技术分析表征了分子筛型 PAN- ACF的吸附性能和表面结构 .结果表明 :浸渍煤焦油后的 PAN-ACF在 100～ 400 ℃之间失重缓慢 ,是煤焦油中苯环及杂环类化合物与纤维表面氧化接枝的过程；经 350 ℃浸渍空气氧化 ACF对 N2/O2吸附量及选择性均得到了显著提高 ,选择系数达到 5.6；浸渍煤焦油的 PAN-ACF表面具有一定量的羟基、醚基、羰基和羧基等含氧官能团 ,氧化过程中各类官能团含量发生改变 ,类石墨碳含量随浸渍浓度增加而增大；浸渍氧化再炭化的结果使 PAN-ACF对 N2/O2吸附选择性得到明显提高 .