Elimination of odours from the gaseous phase on Cr-III- and Fe-III-modified Y-type zeolites

Modified NaY-type zeolites, in which a portion of the sodium ions had been exchanged for chromium(III) or iron(RI) ions, were studied as adsorbents. T he modified zeolites were tested with respect to the adsorption of n-butyla mine or n-butylthiol via the pulse method employing a column micro-adsorber directly attached to a gas chromatograph. Thus, 200 mg portions of the ads orbent were activated by heating at 400 degreesC for 2 h after which the te mperature was decreased to 200 degreesC. The column was held at this temper ature for I h and then 10 mul portions of n-butylamine and n-butylthiol wer e injected on to it at 15-min intervals. It was found that the zeolites con taining iron(III) ions were much more effective as adsorbents (by 30%) than those containing chromium ions, with this difference reaching 60% in the c ase of n-butylthiol. Furthermore, zeolites containing iron(IH) ions underwe nt much less deactivation than those with chromium(III) ions. Increasing th e iron --> sodium or chromium --> sodium ion exchange led to increased adso rption of the organic compounds studied. It was shown that Y-type zeolites modified with iron(III) are effective adsorbents for deodorising atmospheri c air.