The kinetics of adsorption of organo-phosphorus vapors from air mixtures by activated carbons

✍ Scribed by L.A. Jonas; J.A. Rehrmann

• Publisher: Elsevier Science
• Year: 1972
• Tongue: English
• Weight: 507 KB
• Volume: 10
• Category: Article
• ISSN: 0008-6223
• DOI: 10.1016/0008-6223(72)90073-5

✦ Synopsis

The adsorption characteristics of activated carbons for the vapors of dimethyl methylphosphonate (DMMP) and of isopropyl methylphosphonofluoridate (IMPF) were studied under kinetic flow conditions. The carbon granules were packed to a reproducible bulk density in beds of uniform cross-sectional area and subjected to constant inlet vapor concentration, volume flow rate, and temperature but varying bed weights. The breakthrough time of the vapor through the bed, at an exit concentration equal to 1 per cent of the inlet concentration, was determined for each bed weight, and plotted as a straight line in accordance with the equation for adsorption kinetics. The kinetic saturation capacity of the carbon for each vapor was determined from the slope and the pseudo first order adsorption rate constant from the intercept. Kinetic equations were constructed for each vapor and, when solved simultaneously, showed that the breakthrough time for IMPF could be correlated with that of DMMP in accord with the equation tb (IMPF) = 0.91 I tb (DMMP)-8.86

for activated carbon and tb (IMPF) = 1.084 tb (DMMP)-4.32 for the same carbon after impregnation with copper, silver, and chromium salts. The close agreement between the relationships of these organophosphorus vapors on the two carbons suggests that the prediction of adsorption of one vapor based upon prior characterization with a reference vapor, originally applicable only under equilibrium, can be extended for use under kinetic conditions. A method is presented for calculating the kinetic adsorption capacity of an activated carbon for IMPF from the experimental DMMP value using equilibrium relationships, and shown capable of predicting the capacity within 4.1 per cent.