The desiccants are the substances which are widely used to absorb the moisture, humidity, water vapors and odor. They have the ability to maintain the effectiveness and originality of the products. The main task of air drying desiccants is to dehydrating the air and removes the contaminants to get the pure air. The variety of desiccants can be used for drying, cleaning and purifying the air or gases. These include molecular sieve, silica gel, activated alumina and others.