  Deciphering the interplay between confinement effects and intermolecular
interactions in zeolites is crucial for understanding diverse diffusion
behaviors of confined molecules. Recent studies explored the impact of water
and CO$_2$ on hydrocarbon dynamics in nanoporous materials. However, differing
nanoporous materials, as used in these studies complicate the comparative
analysis of CO$_2$ and water effects on hydrocarbons, necessitating a
comprehensive investigation with identical confining media and consistent pore
diameters. In this study, we investigate the diffusion of ethane, CO$_2$, and
water in ZSM-22 molecular sieves. Additionally, we examine the effect of
hydration and CO$_2$ on ethane diffusion through the study of ethane-water and
ethane-CO$_2$ mixtures. Results indicate enhanced translational motions of
CO$_2$ in mixtures, while CO$_2$ minimally affects ethane diffusion. In
contrast, water is found to slow down the diffusion of ethane by making
molecular bridges across the pores. Ethane hampers the translational dynamics
of water molecules. Hydrogen bonding in water and the molecular polarity of the
fluids are found to play an important role in determining the effects of the
presence of one species on the motion of the other. Rotation of the fluid
molecules in ZSM-22 is found to occur at two-time scales in both pure state as
well as in fluid mixtures. While the short-time fast rotation is determined by
the moment of inertia, the long-time rotation is affected by the interaction
between fluid molecules and the zeolite atoms. In the case of water, hydrogen
bonding hinders rotation and inhibits complete rotation.
