Preparation of Activated Fibrous Carbon from Phenolic Fabric and Its Molecular Sieving Properties

Abstract

The phenolic fabrics (Kynol) were applied as precursors to prepare the molecular sieving i activated fibrous carbons(AFC) which had different properties such as pore volume, pore diameter and surface area, etc. The carbonization or pyrolysis in pure N2, and the direct activation under CO2, H2O or exhaust of propane(LPG) combustion were carried out at 300~1490°C (mainly at 800~1000°C). For comparison, the activated granular carbons(AGC) were also prepared from two kinds of coconut shell by conventional two step process pf carbonization and activation in series. Dynamic processes of the development of porous structure Were compared AFC with AGC Detailed characterizations were conducted on the physical pore sturcture and the adsorption capacities for benzene, cyclohexane and water in gaseous phase and for iodine in liquid phase. Main results obtained were as follows : (1) AFC were obtained with the yield of 10 to 30% by mass, and the surface area attained as high as 2000~3000 m2/g. The pore distribution curves of AFC measured by the adsorption of water were the ideal monodisperse type. The total pore volume, Vp(t) attained 1. 2 cm3/g covering the radius over the range of 0, 7~1. 5 nm. (2) The pore distribution curves of AGC were multidisperse type. The Vp(t) attained 1.6cm3/g, but about 1/3 of Vp(t) belonged to the pore whose radius was larger than 10 nm. (3) The pore opening of AFC was deduced to be a slit like, and the molecular sieving effect Over AFC resulted in the selective adsorption of benzene to cyclohexane to be 16 to 1 by mass. (4) It was confirmed that the pore diameter of AFC was manageable by subtle control of the extent of activation and/or the severity of carbonization conditions. (5) A commercial activated granular carbon prepared from coal was also used as a refers ence, and found to be very close to AGC in the porous properties and adsorptive behavipurs. © 1987, The Chemical Society of Japan. All rights reserved.