A theoretical study of swelling and shrinking of hydrated Wyoming montmorillonite

► Hysteresis is easily realisable in MMT with divalent cations in interlayer space. ► Hysteresis is obvious in MMT including small counterions than big ones. ► Different mechanisms of forming hydrogen bonds let to hysteresis phenomenon. ► Predictions were proposed about swelling and shrinking of MMT with heavy metal cations.