Super microporous (pore size = 7–20 Å) and mesoporous (pore
size = 20–500 Å) adsorbents have been found preferable for the
adsorption of the relatively large-size siloxanes, such as D4
(10 Å kinetic diameter) [12,23,27,28]. Yu et al. [12] investigated
the effect of the main textural properties of adsorbents when siloxanes
are removed. The adsorbents with pore sizes distributed
around 17-30 Å have the largest adsorption capacity. A recent
study by Cabrera-Codony et al. [13] further proved that the mesopore
volume was related more to the D4 adsorption capacity than
the larger micropore volume, and the narrow micropore volume
(17 Å) for siloxane adsorption is imperative