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°C and KOH activation at 600–800°C. Steam activation yielded relatively poorly developed porosity regardless of the activation temperature, maintaining a low surface area (around 700 m2 g−1) at very high burn-off, while KOH activation provided high porosities above 700°C. 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 (∼9 μmol SO2 g−1 min−1) than for steam activated fibers (∼4 μmol 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.