Characterization of adsorbent materials supported on polyurethane foams by nitrogen and toluene adsorption

Different composite adsorbent materials were obtained by supporting three activated carbons, one zeolite and one pillared clay, in a polyurethane foam. Adsorption isotherms of nitrogen and toluene were determined to evaluate the influence of the supporting process in the adsorption capacity of the different adsorbent materials. The results indicate that the activated carbons in form of pellets presented the best results with a decrease of about 20% in the nitrogen adsorption capacity but maintaining the same toluene adsorption capacity. The inorganic adsorbents presented a decrease of about 73% for the zeolite and 97% for the pillared clay in the nitrogen adsorption capacity and also a pronounced decrease in the toluene adsorption capacity. Two materials, one activated carbon and one zeolite, with different particle sizes were supported in the polyurethane foam. The decrease in the adsorption capacity of nitrogen and toluene was more pronounced when solids with smaller particles were used. This was an indication that the decrease in the adsorption capacity is related to the impregnation of the surface of the solid particles by the polyurethane during the synthesis of the composite material, which was observed by scanning electron microscopy. Nevertheless, the supporting method, in a one step procedure, presented itself with good possibilities for applications with activated carbons in the form of pellets.