All MC moves attempted to insert a NaCl unit in the zeolites filled with water were rejected, and registered value of W used to construct the histograms are associated to much lower insertion probabilities. This enables us to conclude that in the frame of our model, electrolyte does not penetrate inside the zeolites. On the microscopic scale, a silanol defect is not singularly different from a water molecule because silanol hydroxil group play the same role in solvating Cl -anion than those of water molecule. The intrusion and extrusion of various electrolyte (NaCl, NaBr and CaCl 2 ) at 2 and 3 M in pure-silica chabazite has been investigated in detail in an earlier work to be discussed in the context of our simulations. Characterizations of chabazite samples before and after intrusion using Si solid-state NMR spectroscopy confirm formation of silanol defects upon intrusion of NaCl electrolyte solution, resulting in a lowering a the intrusion pressure in the second and third intrusion cycle, from 54 to 47 and 44 to 38 MPa for respectively 2 and 3 M solution. This indicates that despite increasing amount of silanol defects in the chabazite, it remains hydrophobic.