A particularly important concept that we would like to highlight
here was widely elaborated by Derouane and it is related to
the confinement effect of zeolites on adsorbing/diffusing molecules
throughout its micropore environment. In fact, every introductory
course on zeolites readily highlights the confinement as the most
ubiquitous and intriguing fingerprint of zeolites, whose effect is
at the same time essential and difficult to quantify. Apart from
Derouane’s contributions – which we analyse here – few studies, if
any, have been addressed to attempt a fundamental understanding
of the confinement effect in zeolites [2–5].