Simple preparation of high concentration Nd3+-modified NaY zeolites with lower desorption activation energy of water

Abstract

High concentration Nd3+-modified zeolite NaY with 22.6 wt% Nd element contained has been successfully prepared by a simple re-doping method via 4-fold ion-exchange and subsequent calcination treatments. This re-doping method not only provides a way to incorporate as high contend Nd cations within zeolite, but also proves the ion migration theory from experimental prospective. The obtained Nd-NaY zeolites are characterized by X-ray powder diffraction (XRD), Inductive coupled plasma (ICP), Scanning electron microscopy (SEM), etc, illustrating the Nd3+ cations can migrate into the sodalite cages from supercages, which leads to the lattice distortion of zeolite structure. With the addition of more Nd3+ ions, the average pore of the Nd-NaY zeolites has increased slowly while the specific surface area decreases. We found the values of reduce desorption activation energy (Ed) of water decrease gradually with the introduction of Nd3+ cations when it used as adsorptive materials. When the Nd3+ content of zeolite reaches 22.6 wt %, the value of Ed of water decreases to 154.7 kJ/mol. This research provides highly application value to reduce water molecules desorption activity energy as potential adsorptive materials in rotary dehumidification wheel.