Adsorption of phosgene and chloroform by activated and impregnated carbons

Equilibrium adsorption and desorption isotherm data at room temperature have been obtained for phosgene and chloroform vapors on BPL grade activated carbon, ASC whetlerite and four ASB impregnated carbons. Isotherm data were plotted in the form of the Dubinin-Polanyi equation. Experimental affinity coefficients (β_ex) for phosgene with chloroform as a reference, were calculated for all the carbons except ASC whetlerite from the slopes (k) of the Dubinin-Polanyi plot, and were compared with the theoretical affinity coefficients (β_th) in order to assess the adsorption capabilities of different adsorbents. In the case of phosgene on ASC whetlerite carbon, significant chemisorption takes place along with physical adsorption and the resulting isotherm shows non-linear behavior. Attempts were made to separate the chemisorption contribution from the total adsorption and thus assess β_ex for the physical adsorption contribution.