Using the Wheeler-jonas Equation to Describe Adsorption of Inorganic Molecules: Ammonia

Activated carbons can adsorb a wide variety of substances. This is the reason why they are used in canisters to guarantee the safety of the people. The use of the canisters is dependent on several parameters which makes it interesting if the safety margins of the filter can be predicted. The Wheeler-Jonas equation is a well-known predictive equation for describing organic vapour breakthrough times of activated carbon beds [1]. The parameters of this equation can be linked to the micropore volume of the carbon and the kinetics of the adsorption process (mass transfers) for physisorped, i.e. organic vapours. Inorganic vapours are usually chemisorbed at the active sites of the carbon surface. Nevertheless, it would be beneficial if a Wheeler-Jonas equivalent equation could be derived for inorganic vapours. The applicability of the Wheeler equation has been proven earlier for cyanogen chloride [2], but not for other inorganic vapours. This paper investigates the validity of the Wheeler-Jonas equation for the adsorption of inorganic vapours, in particular ammonia.