Preparation of highly activated carbon fiber by surface modification

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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