A New Amorphous Aluminum-Silicate : High Performance Adsorbent for Water Vapor and Carbon Dioxide

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 29 Si and 27 Al 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°C. The amorphous aluminum-silicate also