Application of Sn-activated carbon in pressure swing adsorption for purification of H-2

Sn-activated carbon (Sn-AC) in pressure swing adsorption (PSA) system has b een successfully used in the purification of hydrogen for PEM fuel cell app lication. Activated carbon was impregnated with 34.57% SnCl2. 2H(2)O salt a nd then dried at 180 degrees C to produce AC-SnO2 to improve its adsorptive interaction with CO. The amount of CO adsorbed was almost equal to that de sorbed which could imply that the adsorption of CO on the prepared adsorben ts seems to be reversible. Further exploitation of the impregnated activate d carbon in PSA experiments showed that adsorption of carbon monoxide was h igher with the impregnated carbon than in the pure carbon. The concentratio n of carbon monoxide, which was 1000 ppm, was successfully reduced to 40.2 and 10.4 ppm by the pure and the impregnated activated carbons, respectivel y. Besides the fact that activated carbon has its original different pore s izes for normal gas phase CO adsorption (as in case of pure carbon), the im pregnated carbon has additional CO adsorption ability due to the presence o f O-(ads) on the active sires. The use of AC-SnO2 in adsorbing CO proved su perior to that when pure carbon was used for H-2 purification in a PSA syst em. Discernibly, the high adsorptive selectivity of AC-SnO2 towards gas-pha se CO portrays a good future for the applicability of this noble adsorbent, since CO imposes its own threat in the current level of air pollution. (C) 2000 Elsevier Science Ltd. All rights reserved.