Abstract
To develop a humidity self-controlling material, mesoporous clay samples have been prepared through selective leaching of calcined Chinese kaolinitic-clays (Suzou-Kaolin, Coal-Kaolin and Black Clay). These samples were calcined for 1 hour at 900°C, 1000°C, and 1100°C. Each 100g of the calcined samples was suspended in 500ml of 1N KOH solution for 24 hours at 90°C. The mesoporous clay materials obtained from Suzou-Kaolin and Coal-Kaolin showed a very narrow pore size distribution at around 20-30Å in pore radius and with the specific surface areas at around 90m2/g and 70m2/g. The total pore volumes were 0.20m1/g for Suzou-Kaolin and 0.12m1/g for Coal-Kaolin, respectively. The water vapor adsorption isotherms showed a rapid increase at relative humidity (RH) of about 60%. The amount of water vapor adsorption at RH=90% for the same samples were 14mass% and llmass%, respectively. On the other hand, Black-Clay which contains small amount of impurity iron, alkali and alkaline earth elements, showed a gradual increase in water vapor adsorption up to RH=90%. From the results of water vapor adsorption and desorption measurements, the mesoporous materials prepared through selective leaching of silica from calcined Chinese kaolinitic clays (SuzouKaolin and Coal-Kaolin) showed good quality samples for humidity self-controlling material.
