product was neutralized with aqueous ammonia and then filtered through no 5 filter paper manufactured by toyoroshi kaisha ltd the filtrate was concentrated to obtain a spinning material in the form of a solution containing 34 by weight of water and having a viscosity of 100 centipoises at 85 u00b0 c the resulting salt of the condensation product had a number average molecular weight of 4 300 this spinning material was dry spun using a stainless steel spinneret having an orifice diameter of 0 1 mm the spun fiber was directly subjected to a carbonization step specifically the fiber was fired in a stream of n 2 by raising the temperature from room temperature to 800 u00b0 c at a rate of 10 u00b0 c min the resulting carbon fiber had a diameter of 12 u03bcm a tensile strength of 65 kg mm 2 a specific surface area of 250 m 2 g as measured by the co 2 bet method and a specific surface area of 30 m 2 g as measured by the n 2 bet method moreover when measured at 25 u00b0 c under 3 atmospheres its equilibrium co 2 adsorption was 188 ml g and its equilibrium n 2 adsorption was 25 ml g furthermore the above fiber was activated by treatment with steam at 850 u00b0 c for 60 minutes the resulting fiber had a specific surface area of 1 470 m 2 g as measured by the co 2 bet method and a specific surface area of 1 560 m 2 g as measured by the n 2 bet method 1 700 g of creosote oil was mixed with 1 050 g of.