Water vapor adsorption performance of Ag and Ni modified 5A zeolite

In this work, Ag and Ni metals incorporation effect on the water adsorption and physicochemical properties of 5A zeolite was studied. For that, Ag/5A and Ni/5A zeolites with different amounts of metal (4, 10 and 20 wt%) were prepared by wet impregnation method. The physicochemical characterization of the adsorbents was carried out by N2-adsorption, AAS, XRD, FTIR, FE-SEM/EDS, H2-TPR, CO2-TPD and TGA-DSC analyses. The results showed that the incorporated metals were well distributed in different sites into the 5A zeolite, without a substantial modification of its crystal structure and morphological characteristics. Water vapor uptake and water enthalpy adsorption of zeolites were determined simultaneously by a non-isothermal method in a TGA-DSC thermal analyzer, prior saturation of samples with water vapor. It was found that the water molecules adsorption by the metal/zeolites was carried out on different adsorption sites with different interaction energies. Furthermore, it was noted that Ag and Ni metals had a remarkable influence on water adsorption properties of zeolites. Metal addition favored the superficial adsorption of water molecules per available area of zeolite, with high adsorption enthalpy values. This makes the prepared adsorbents potential materials to be used in thermal storage applications and waste heat recovery systems.