The effect of flow pattern on adsorption of dimethyl methyl phosphonate in activated carbon beds and canisters Original Research Article

Breakthrough times (tB) of activated carbon, at constant rate and pulsating (breathing-simulation) flow challenge of dimethyl methyl phosphonate (DMMP), an accepted simulant for organophosphorus warfare agents, were obtained. For personal filter canisters, tB at pulsating flow rates of 30 or 45 l min−1 on the average were found to be shorter than tB obtained at fixed flow rates by 4 and 6%, respectively. The shortening of tB by pulsating flow patterns relative to fixed flow is explained in terms of the critical bed weight as used in the Wheeler-Jonas model. The difference in tB between pulsating and fixed flow rate is expected to increase with decreasing bed depths that approach the critical bed depth.