Further Observations on the Displacement of Pre-adsorbed Water from BPL Activated Carbon by Chloropicrin Vapour

The efficiency of adsorption of chloropicrin vapour from a flowing airstream by beds of BPL activated carbon has been measured as a function of the relative humidity and temperature. The results show that there is a complex relationship between the kinetic adsorption performance and environmental parameters. In particular, the displacement of pre-adsorbed water can be critical. In several situations that reflect practical usage the effluent airstream is not able to remove water from the filter bed as fast as it is displaced (because it quickly reaches saturation). In such cases there is a fine balance as to whether water accumulation in the transport pore structure of the carbon results in pore blockage and thereby prevents the system reaching thermodynamic equilibrium, or whether build-up occurs in the intergranular spaces where it has only a limited effect.