Hydration rate of allophane and imogolite by hydration heat measurement - Using as heat exchange absorbents for lower temperature heat source and speedy drying desiccant

The hydration rate of allophane and imogolite has been estimated by means of an adiabatic vapor absorption calorimeter. The hydration amount of allophane and imogolite were 16.6 and 19.4%, respectively, at dehydrated temperature of 100 degreesC. The maximum hydration rate of allophane and imogolite were 0.063 mmol/g(.)s and 0.087 mmol/g(.)s, respectively, at same dehydration temperature. When allophane and imogolite were dehydrated at temperatures below 100 degreesC, the hydration rate of allophane was larger than that of Mg-A type zeolite, and the hydration amount of allophane was larger than that of B type silica gel. Both hydration rate and hydration amount of imogolite were larger than those of Mg-A type zeolite and B type silica gel. Therefore, allophane and imogolite are suitable for heat exchange absorbents of the heat pump and speedy drying desiccant.