Impact of ion exchange on zeolite hydrophilicity/hydrophobicity monitored by water capacity using thermal analysis

Zeolite coatings consisting of a mixed phase of LTA and FAU type zeolites, prepared originally in Na form, were exchanged by Li, Mg and Ce ions. The effects of ion exchange on hydrophilicity/hydrophobicity as well as water capacities at relatively low and high temperatures were investigated by thermogravimetry (TG). The same investigations were also carried out for pure phases of powder zeolites NaA, NaX and NaY. It was determined that ion exchange might have significant effects on hydrophilicity/hydrophobicity and water capacities of zeolites in case favorable ions and suitable exchange conditions are used. Enhancements of about 50% were obtained in the hydrophobicity index and water capacity values at 100 °C when zeolite coatings in Na form were exchanged by Ce and Mg, respectively. The improvements obtained by Mg and Ce exchanges were determined to be related to different effects of these ions on LTA and FAU type zeolite phases, respectively.