Adsorption isotherms are reported for pure carbon dioxide and water vapor on 5A and 13X zeolite beads and silica gel granules. These data were obtained using a volumetric method and cover the temperature ranges of (-45 to 175) degrees C for carbon dioxide and (0 to 100) degrees C for water. Also, pure carbon dioxide isotherms on silica gel at temperatures from (10 to 55) degrees C were measured using a gravimetric apparatus. All pure component equilibria are described well by Toth isotherms with parameters having temperature dependence. For carbon dioxide adsorption, zeolites 5A and 13X have similar loadings and show a much higher capacity than silica gel. However, for water vapor, zeolite 13X has a slightly higher capacity than zeolite 5A. Both zeolites have very good adsorption capacities for water vapor at low pressures but lose their advantages to silica gel when water pressures are high.