Preparation of highly activated carbon fiber by surface modification

采用苯化学气相沉积法对一系列活性炭纤维进行了孔径控制，探讨了孔径分布对活性炭纤维孔径的影响。通过CVD的重量增加被发现在一定水平上饱和，相应于纤维，反映了它们的表面积。但只有比表面积较小的纤维才具有对CO_2和CH_4的分子筛选择性，而比表面积较大的纤维则失去了对这两种气体的吸附活性。碳沉积在孔壁表面，控制从表面延伸的直孔的狭缝尺寸，而苯分子可以进入孔中。1.以沥青基活性炭纤维（ACF）为催化剂，研究了1，2-二氯乙烷（1，2-DEC）催化脱氢合成氯乙烯（VC）的反应。通过化学气相沉积（CVD）的含氮化合物的ACF的表面改性表现出更高的催化活性和更长的寿命在非常高的相对活性比薄的接收形式。X射线光电子能谱（XPS）分析表明，改性纤维表面的吡啶氮通过其碱性催化选择性脱氯化氢反应，自由基消除受到抑制，从而延长了使用寿命

Pore size control of a series of active carbon fibers was attempted by CVD of benzene to clarify the influences of the pore distribution. Weight increase by CVD was found saturated at the certain level respective to the fiber, reflecting the their surface areas. However, the molecular sieving selectivity between CO_2 and CH_4 was induced only to the fibers of smaller surface area, while the fibers of larger surface areas lost the adsorption activity against both gases. Straight micropores developed from the surface are controlled at their slit size by carbon deposition onto the wall surface while benzene molecule can get into the pore. In contrast, the pore size of micropores developed on the wall of mesopore are difficult to be controlled since the carbon deposit continues until the whole wall of the mesopores is covered by the carbon to plug the microporesCatalytic denydrochlorination of 1, 2-dichloroethane(1, 2-DEC) into vinyl chloride(VC) was carried out over pitch-based active carbon fiber s(ACF). Surface modification of the ACF by Chemical Vapor Deposition(CVD) of N-containing compounds showed higher catalytic activity and longer life time at very high ralectivity than thin as-received forms. X-ray photoelectron spectroscopy(XPS) suggested that pyridinic nitrogen found on the surface of the modified fibers catalyzes the selective dehydrochlorination reaction through its basicity, radical elimination appearing suppressed to provided longer life