The ability of two very different active carbons, a polymer-derived carbon (with ultramicropores and supermicropores and a large volume of 'transport' pores) and a coconut shell-derived carbon (predominantly ultramicroporous), to reduce the levels of volatile toxicants in cigarette smoke has been measured and compared. The polymer-derived carbon was found to be approximately twice as effective in removing the majority of measured smoke vapour phase toxicants compared to the coconut-shell derived carbon in 3 different cigarette formats and with 2 different smoking regimes.

By applying adsorption first principles to equilibrium isotherm data and also measuring dynamic breakthrough times and volumes, we have established criteria by which active carbon performance for removing various toxicants from challenge streams (characterized by relatively high flows per weight of carbon and short contact times) can begin to be understood. This approach identifies some of the key factors which influence dynamic toxicant adsorption.

Single component dynamic breakthrough experiments were conducted with benzene, acrylonitrile and 2-butanone at 298 K for beds of each carbon under dry (0%RH) and wet (60% RH) conditions. Longer breakthrough times were found with the polymer-derived carbon, and breakthrough times recorded under wet conditions were found to be up to 20% shorter than those obtained under dry conditions. Correlations were found between micropore volume, dynamic adsorption volume and filter bed breakthrough time.