Abstract
An efficient adsorbent made of hydroxyl aluminum-silicate has been developed for a desiccant air conditioning system and a carbon dioxide capture system. The XRD pattern shows that this adsorbent is amorphous, and the 29Si and 27Al NMR spectra show that the chemical species of Al and Si in some part of this adsorbent is similar to allophane and/or imogolite and those in the other part is similar to layered clay minerals. The amount of water-vapor adsorbed on this adsorbent is 36 wt% when the relative water-vapor pressure is at 0.6. This value is 1.4 times larger than the amount of water-vapor adsorbing on zeolite A, which is now used for the desiccant air conditioning system. Our newly developed hydroxyl aluminum-silicate is better than zeolite A for the adsorbent used in the desiccant air conditioning system because it adsorbs water-vapor in a wide humidity range and can desorb at the temperature as low as 80℃. The amorphous aluminum-silicate also adsorbs much carbon dioxide. The amount of adsorbed carbon dioxide on this material is 11.1 wt% when the pressure of carbon dioxide is raised from 100kPa to 900kPa. This value is 2.1 times larger than the amount of carbon dioxide adsorbing on zeolite X, which is now used for a carbon dioxide capture system. If the pressure swing adsorption (PSA) system can be operated more than the atmospheric pressure by using this material, the newly developed materials can collect carbon dioxide with low cost compared with the present system.
