PAN-based activated carbon fiber composites for sulfur dioxide conversion:: influence of fiber activation method

Activated carbon fibers (ACF) were prepared from poly(acrylonitrile) (PAN) precursor fibers by two methods: steam activation at 650-1000 degreesC and KOH activation at 600-800 degreesC. Steam activation yielded relatively poorly developed porosity regardless of the activation temperature, maintaining a low surface area (around 700 m(2) g(-1))at very high burn-off, while KOH activation provided high porosities above 700 degreesC. However, at ratios of KOH to fiber greater than 1:1 wt/wt, the fiber morphology was destroyed. The SO2 conversion activity of the ACF was studied in the presence of oxygen and water. The activity was higher for as-produced KOH-activated samples (similar to9 mu mol SO2 g(-1) min(-1)) than for steam activated fibers (similar to4 mu mol SO2 g(-1) min(-1)), and correlated with lower oxygen content in the product fibers. The ACF were also used to manufacture composites. Composites retain the catalytic activity of the parent ACF. (C) 2001 Elsevier Science Ltd. All rights reserved.