In this work, we study the structural response of MFI, FAU and LTA type zeolite powders to the presence of cations commonly found in sea salts including Na+, K+, Ca2+, and Mg2+. Zeolite powders were exposed to seawater solution (3.8wt% (TDS) ), and the structure of the zeolite powders was characterized by synchrotron X-ray powder diffraction. The results obtained from ion adsorption testing and synchrotron Xray powder diffraction showed that the zeolites interacted with monovalent and divalent cations, and these interactions altered the crystal dimensions of the zeolites. The changes in structure could possibly affect diffusion properties of these materials when used as membranes for desalination.