By using NaY zeolites as desiccant materials, commercial NaY zeolite was alkali treated with 1 M NaOH aqueous solution and then Mg2+ ion-exchanged by 0.5 M Mg(NO3)(2) aqueous solution. Alkali treatment (AT) of NaY zeolite removed silicon atoms selectivity from the framework of Y-type zeolite and enhanced water diffusivity of Y-type zeolite. On the other hand, Mg2+ ion-exchange of NaY zeolite increased the amount of water adsorbed. Prepared Y-AT-Mg zeolite had both water adsorption velocity and a large difference of water adsorbed amount between adsorption at 30 degrees C and desorption at 100 degrees C. (C) 2015 Elsevier Inc. All rights reserved.