Remarkable Catalytic Activity of Calcined Pitch Based Activated Carbon Fiber for Oxidative Removal of SO2 as Aqueous H2SO4

Abstract

Catalytic activity of a series of pitch-based activated carbon fibers (ACFs) was examined at room temperature for the oxidative removal of SO2 as aqueous H2SO4 which was continuously recovered at steady state. Calcination up to 900 °C in an inert atmosphere increased the activity very markedly regardless of the ACF; however, higher temperatures up to 1200 °C increased the activity of ACFs with larger surface area (1000 m2/g) while the ACFs with smaller surface area lost activity very sharply. ACF with the largest surface area and calcined at 1100 °C resulted in the complete capture of 1000 ppm SO2 by ACF weigh/flow rate (W/F) 1 × 10-3 g·min/mL under 10% H2O. Lower humidity reduced the activity, although larger W/F allowed complete removal of SO2. TPDE measurements revealed CO evolution from the ACF in the range of 400−1100 °C, the amount and the range depending on the ACF. ACF with the highest activity appeared to be obtained when the major CO-evolving groups were removed before marked reduction of the su...