Abstract
The effect on the adsorption behavior of cigarette smoke constituents by activated carbon in cigarette filters was investigated. Two kinds of activated carbon with comparable micropore and mesopore volumes were used, but one had macropores (AC-1) and the other did not (AC-2). These showed similar adsorption isotherms for benzene. But the adsorption efficiencies for benzene contained in the cigarette smoke using the puff-by-puff smoking system were significantly different: AC-1 indicated high adsorption efficiency until the last puff but the adsorption efficiency of AC-2 decreased at an early puff. Meanwhile, it was found that the adsorption rate for benzene vapor of AC-1 was faster than that of AC-2 in fixed-bed adsorption tests. Since the macropores play a key role in diffusion paths through which an adsorbate molecule reaches into the micropores, it can be inferred that they affect the adsorption rate. Additionally, the results from a two-component test using benzene and water suggested that competitive adsorption reduced the adsorption rate of benzene. Thus, we inferred that the difference of the adsorption rate of benzene contained in the cigarette smoke would be enhanced by competitive adsorption of the complex constituents in the cigarette smoke, resulting in the significant difference in the adsorption efficiencies for benzene in the puff-by-puff smoking system.
