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 poo rly developed porosity regardless of the activation temperature, maintainin g a low surface area (around 700 m(2) g(-1))at very high burn-off, while KO H activation provided high porosities above 700 degreesC. However, at ratio s of KOH to fiber greater than 1:1 wt/wt, the fiber morphology was destroye d. The SO2 conversion activity of the ACF was studied in the presence of ox ygen and water. The activity was higher for as-produced KOH-activated sampl es (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 con tent in the product fibers. The ACF were also used to manufacture composite s. Composites retain the catalytic activity of the parent ACF. (C) 2001 Els evier Science Ltd. All rights reserved.