Finally, AIMD simulations including co-adsorbed water molecules showed that the water molecules have a higher affinity towards the framework protons, displacing 5-FU from their vicinity. Thus, it seems unlikely that interactions with the framework protons would contribute significantly to the stabilisation of 5-FU in zeolite pores in the presence of water. In the context of contaminant removal, it is therefore pivotal to maximise adsorbent hydrophobicity, as already discussed in earlier work, for example, for the case of triclosan adsorption. For drug delivery, on the other hand, there are some additional implications: If 5-FU was loaded in the absence of water (e.g., from non-aqueous solvents like acetone, as reported in some previous studies ) and the 5-FU@zeolite composite stored without exposure to humidity, the drug could be released upon contact with water, for example, in the human body.